numeric.c: raise TypeError for non-Integer bitwise operands

Integer#&, #| and #^ read the right-hand operand with mrb_integer() without checking its type. For a Float (or any non-Integer) this reads an unrelated union field and returns a garbage value instead of raising, as CRuby does. Raise TypeError via mrb_int_noconv() when the operand is not an Integer. Bigint operands are still handled before this point, and the shift operators keep coercing their width as before. Co-authored-by: Claude <noreply@anthropic.com>
random.c: fix signed integer overflow in rand() with integer ranges
2026-06-08 16:11:16 +00:00 · 2026-06-05 11:23:43 +09:00 · 2026-06-05 11:23:43 +09:00 · 2026-06-05 07:43:35 +09:00 · 2026-06-04 17:37:12 +02:00 · 2026-06-04 17:36:41 +02:00
250 changed files with 20191 additions and 6324 deletions
@@ -5,11 +5,29 @@ updates:
    directory: "/"
    schedule:
      interval: "daily"
    groups:
      bundler-dependencies:
        patterns:
          - "*"
    cooldown:
      default-days: 7
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "daily"
    groups:
      github-actions-dependencies:
        patterns:
          - "*"
    cooldown:
      default-days: 7
  - package-ecosystem: "pre-commit"
    directory: "/"
    schedule:
      interval: "daily"
    groups:
      pre-commit-hooks:
        patterns:
          - "*"
    cooldown:
      default-days: 7
@@ -31,7 +31,9 @@ jobs:
      LD: ${{ matrix.cc }}
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Compiler version
@@ -44,11 +46,13 @@ jobs:
    timeout-minutes: 15
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Cache cosmocc
-        uses: actions/cache@v5
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
        id: cache-cosmocc
        with:
          path: ~/cosmo
@@ -70,7 +74,9 @@ jobs:
      MRUBY_CONFIG: ci/msvc
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Build and test
@@ -18,14 +18,16 @@ jobs:
        language: ["actions"]
    steps:
      - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4
+        uses: github/codeql-action/init@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4.36.0
        with:
          languages: ${{ matrix.language }}
      - name: Autobuild
-        uses: github/codeql-action/autobuild@v4
+        uses: github/codeql-action/autobuild@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4.36.0
      - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4
+        uses: github/codeql-action/analyze@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4.36.0
        with:
          category: "Security"
@@ -2,6 +2,9 @@ name: Coverage
 on: [push]
 permissions:
  contents: read
 jobs:
  coverage:
    name: Coverage
@@ -16,7 +19,9 @@ jobs:
      LDFLAGS: --coverage
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - name: Ruby version
        run: ruby -v
      - name: Compiler version
@@ -34,7 +39,7 @@ jobs:
            echo \`\`\`
          } > "$GITHUB_STEP_SUMMARY"
      - name: Upload coverage report
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: coverage-${{ github.sha }}
          path: coverage/
@@ -9,7 +9,7 @@ jobs:
      pull-requests: write
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/labeler@v6
+      - uses: actions/labeler@f27b608878404679385c85cfa523b85ccb86e213 # v6.1.0
        with:
          repo-token: "${{ secrets.GITHUB_TOKEN }}"
          sync-labels: true
@@ -11,7 +11,9 @@ jobs:
    name: Run ls-lint
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - uses: ls-lint/action@v2.3.1
+        with:
          persist-credentials: false
      - uses: ls-lint/action@02e380fe8733d499cbfc9e22276de5085508a5bd # v2.3.1
        with:
          config: .github/linters/.ls-lint.yml
@@ -20,7 +20,7 @@ jobs:
          fuzz-seconds: 600
          dry-run: false
      - name: Upload Crash
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        if: failure()
        with:
          name: artifacts
@@ -0,0 +1,22 @@
 # https://github.com/j178/prek
 name: Manual hooks
 on: [pull_request]
 permissions:
  contents: read
 jobs:
  pre-commit:
    name: Run pre-commit
    runs-on: ubuntu-latest
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - uses: j178/prek-action@bdca6f102f98e2b4c7029491a53dfd366469e33d # v2.0.4
        with:
          install-only: true
      - name: Run manual pre-commit hooks
        run: prek run --color=always --all-files --hook-stage manual
@@ -12,9 +12,9 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - uses: j178/prek-action@v1
+        with:
          persist-credentials: false
      - uses: j178/prek-action@bdca6f102f98e2b4c7029491a53dfd366469e33d # v2.0.4
        with:
          extra-args: --all-files
      - name: Run manual pre-commit hooks
        run: prek run --color=always --all-files --hook-stage manual
@@ -19,7 +19,9 @@ jobs:
      fail-fast: false
    steps:
      - name: "Checkout ${{ github.ref_name }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false
      - name: Builds
        id: builds
        run: |
@@ -38,7 +40,7 @@ jobs:
            mv .sha256 "$packagename.sha256"
          )
      - name: Release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@b4309332981a82ec1c5618f44dd2e27cc8bfbfda # v3.0.0
        with:
          draft: true
          prerelease: ${{ contains(github.ref_name, '-rc') }}
@@ -15,12 +15,13 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          # Full git history is needed to get a proper list of changed files within `super-linter`
          fetch-depth: 0
          persist-credentials: false
      - name: Lint Code Base
-        uses: super-linter/super-linter/slim@v8.5.0
+        uses: super-linter/super-linter/slim@9e863354e3ff62e0727d37183162c4a88873df41 # v8.6.0
        env:
          # VALIDATE_BASH_EXEC: true
          VALIDATE_DOCKERFILE_HADOLINT: true
@@ -3,7 +3,7 @@
 default_stages: [pre-commit, pre-push]
 default_language_version:
  python: python3
-  node: 24.11.1
+  node: 24.14.0
 minimum_pre_commit_version: "3.2.0"
 exclude: "^tools/lrama/"
 repos:
@@ -15,6 +15,9 @@ repos:
      - id: check-hooks-apply
        name: run check-hooks-apply
        description: check hooks apply to the repository
      - id: check-useless-excludes
        name: run check-useless-excludes
        description: clean up unnecessary exclusion patterns
  - repo: local
    hooks:
      - id: prettier
@@ -24,6 +27,16 @@ repos:
        files: \.(md|ya?ml)$
        language: node
        additional_dependencies: ["prettier@3.7.4"]
        pass_filenames: false
        stages: [manual]
      - id: check-makefile-indentation
        name: check Makefiles are indented with tabs
        description: ensures that Makefiles are indented with tabs
        entry: ./scripts/check_makefiles_for_tabs.sh
        language: system
        files: "(?i)^makefile$"
        pass_filenames: true # <-- Crucial change: pass filenames to the script
        types: [file] # Ensure only regular files are passed, not directories
        stages: [manual]
      - id: check-zip-file-is-not-committed
        name: disallow zip files
@@ -34,13 +47,13 @@ repos:
          track and have security implications. Please remove the zip file from the repository.
        files: \.zip$
  - repo: https://github.com/gitleaks/gitleaks
-    rev: v8.30.0
+    rev: v8.30.1
    hooks:
      - id: gitleaks
        name: run gitleaks
        description: detect hardcoded secrets with gitleaks
  - repo: https://github.com/oxipng/oxipng
-    rev: v10.0.0
+    rev: v10.1.1
    hooks:
      - id: oxipng
        name: run oxipng
@@ -72,7 +85,7 @@ repos:
      - id: mixed-line-ending
      - id: trailing-whitespace
  - repo: https://github.com/Lucas-C/pre-commit-hooks
-    rev: v1.5.5
+    rev: v1.5.6
    hooks:
      - id: forbid-tabs
        name: run no-tabs checker
@@ -84,19 +97,19 @@ repos:
        args: [--whitespaces-count, "2"]
        exclude: Makefile$
  - repo: https://github.com/rhysd/actionlint
-    rev: v1.7.9
+    rev: v1.7.12
    hooks:
      - id: actionlint
        name: run actionlint
        description: lint GitHub Actions workflow files
  - repo: https://github.com/codespell-project/codespell
-    rev: v2.4.1
+    rev: v2.4.2
    hooks:
      - id: codespell
        name: run codespell
        description: check spelling with codespell
  - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.46.0
+    rev: v0.48.0
    hooks:
      - id: markdownlint
        name: run markdownlint
@@ -105,7 +118,7 @@ repos:
        types: [markdown]
        files: \.md$
  - repo: https://github.com/rubocop/rubocop
-    rev: v1.81.7
+    rev: v1.86.2
    hooks:
      - id: rubocop
        name: run rubocop
@@ -119,7 +132,7 @@ repos:
        name: run shellcheck
        description: check shell scripts with a static analysis tool
  - repo: https://github.com/adrienverge/yamllint
-    rev: v1.37.1
+    rev: v1.38.0
    hooks:
      - id: yamllint
        name: run yamllint
@@ -3,3 +3,4 @@ build
 coverage
 doc/internal/opcode.md
 tools/lrama
 .venv
@@ -1,25 +1,25 @@
 # Authors of mruby (mruby developers)
-## The List of Contributors sorted by number of commits (as of 2026-03-02 02877f0)
+## The List of Contributors sorted by number of commits (as of 2026-05-31 9d084b0)
-   7532 Yukihiro "Matz" Matsumoto (@matz)*
+   7747 Yukihiro "Matz" Matsumoto (@matz)*
-    712 dearblue (@dearblue)*
+    749 dearblue (@dearblue)*
    587 KOBAYASHI Shuji (@shuujii)
    353 Daniel Bovensiepen (@bovi)*
    345 Takeshi Watanabe (@take-cheeze)*
    333 Masaki Muranaka (@monaka)
-    255 John Bampton (@jbampton)
+    266 John Bampton (@jbampton)
    234 Jun Hiroe (@suzukaze)
    228 Tomoyuki Sahara (@tsahara)*
    220 Cremno (@cremno)*
    209 Yuki Kurihara (@ksss)+
-    144 Yasuhiro Matsumoto (@mattn)*
+    146 Yasuhiro Matsumoto (@mattn)*
    113 Carson McDonald (@carsonmcdonald)
    104 Tomasz Pędraszewski (@dabroz)*
     83 Akira Yumiyama (@akiray03)*
     83 skandhas (@skandhas)
     80 Masamitsu MURASE (@masamitsu-murase)
-     73 Hiroshi Mimaki (@mimaki)*
+     79 Hiroshi Mimaki (@mimaki)*
     71 Tatsuhiko Kubo (@cubicdaiya)*
     71 Yuichiro MASUI (@masuidrive)
     62 Yuichiro Kaneko (@yui-knk)+
@@ -36,8 +36,10 @@
     32 Masayoshi Takahashi (@takahashim)+
     31 MATSUMOTO Ryosuke (@matsumotory)*
     30 Nobuyoshi Nakada (@nobu)
     29 HASUMI Hitoshi (@hasumikin)
     26 Hoshiumi Arata (@hoshiumiarata)*
     25 Julian Aron Prenner (@furunkel)*
     23 leviongit (@leviongit)
     22 Clayton Smith (@clayton-shopify)
     22 Uchio Kondo (@udzura)*
     22 Zachary Scott (@zzak)*
@@ -50,10 +52,9 @@
     18 Corey Powell (@IceDragon200)
     18 Hidetaka Takano (@TJ-Hidetaka-Takano)
     18 Jon Maken (@jonforums)+
     18 leviongit (@leviongit)
     18 mirichi (@mirichi)
     17 Mitchell Blank Jr (@mitchblank)*
-     16 HASUMI Hitoshi (@hasumikin)
+     16 Hendrik (@Asmod4n)
     16 bggd (@bggd)
     16 kano4 (@kano4)
     15 Felix Jones (@felixjones)*
@@ -76,7 +77,7 @@
     11 RIZAL Reckordp (@Reckordp)+
     11 Seeker (@SeekingMeaning)
     11 takkaw (@takkaw)
-     10 Hendrik (@Asmod4n)
+     10 Chris Hasiński (@khasinski)
     10 Miura Hideki (@miura1729)
     10 Narihiro Nakamura (@authorNari)
     10 YAMAMOTO Masaya (pandax381)
@@ -88,6 +89,7 @@
      8 Wataru Ashihara (@wataash)*
      7 Bhargava Shastry (@bshastry)*
      7 Kouichi Nakanishi (@keizo042)
      7 Paweł Świątkowski (@katafrakt)
      7 Rubyist (@expeditiousRubyist)
      7 Simon Génier (@simon-shopify)
      7 Terence Lee (@hone)
@@ -101,7 +103,6 @@
      6 INOUE Yasuyuki (@yasuyuki)
      6 Junji Sawada (@junjis0203)
      6 Kenji Okimoto (@okkez)+
      6 Paweł Świątkowski (@katafrakt)
      6 Selman ULUG (@selman)
      6 Yusuke Endoh (@mame)*
      6 buty4649 (@buty4649)
@@ -120,7 +121,6 @@
      5 dreamedge (@dreamedge)
      5 nkshigeru (@nkshigeru)
      5 xuejianqing (@joans321)
      4 Chris Hasiński (@khasinski)
      4 Dante Catalfamo (@dantecatalfamo)
      4 Goro Kikuchi (@gorogit)
      4 Herwin Weststrate (@herwinw)
@@ -140,6 +140,7 @@
      4 Yuji Yamano (@yyamano)
      4 kurodash (@kurodash)*
      4 wanabe (@wanabe)*
      2 0x1eef (@0x1eef)
      3 Anton Davydov (@davydovanton)
      3 Aurora Nockert (@auroranockert)
      3 Carlo Prelz (@asfluido)*
@@ -192,6 +193,7 @@
      2 Masahiro Wakame (@vvkame)+
      2 Minao Yamamoto (@tarosay)+
      2 Nihad Abbasov (@NARKOZ)
      2 Pete Kinnecom (@petekinnecom)
      2 Robert Mosolgo (@rmosolgo)
      2 Russel Hunter Yukawa (@rhykw)+
      2 Ryunosuke SATO (@tricknotes)
@@ -220,6 +222,7 @@
      1 Colin MacKenzie IV (@sinisterchipmunk)
      1 Daehyub Kim (@lateau)
      1 Daniel Varga (@vargad)
      1 David Korczynski (@DavidKorczynski)
      1 Diamond Rivero (@diamant3)
      1 Edgar Boda-Majer (@eboda)
      1 Fangrui Song (@MaskRay)
@@ -274,7 +277,6 @@
      1 Patrick Ellis (@pje)
      1 Patrick Pokatilo (@SHyx0rmZ)
      1 Pavel Evstigneev (@Paxa)+
      1 Pete Kinnecom (@petekinnecom)
      1 Piotr Usewicz (@pusewicz)
      1 Prayag Verma (@pra85)
      1 Ranmocy (@ranmocy)
@@ -282,6 +284,7 @@
      1 Ryan Scott Lewis (@RyanScottLewis)
      1 Ryo Okubo (@syucream)
      1 SAkira a.k.a. Akira Suzuki (@sakisakira)
      1 SaekiMototsune (@saeki-mototsune)
      1 Santiago Rodriguez (@sanrodari)
      1 Satoh, Hiroh (@cho45)+
      1 Satoru Naba (@snaba)+
@@ -325,6 +328,7 @@
      1 sbsoftware (@sbsoftware)
      1 ssmallkirby (@smallkirby)
      1 taku toyama (@tsuichu)
      1 vobloeb (@vobloeb)
 `*` - Entries unified according to names and addresses
 `+` - Entries with names different from commits
@@ -48,7 +48,7 @@ PROJECT_NAME           = mruby
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
-PROJECT_NUMBER         = 3.4.0
+PROJECT_NUMBER         = 4.0.0
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
@@ -2,8 +2,8 @@ GEM
  remote: https://rubygems.org/
  specs:
    coderay (1.1.3)
-    rake (13.3.1)
+    rake (13.4.2)
-    yard (0.9.38)
+    yard (0.9.44)
    yard-coderay (0.1.0)
      coderay
      yard
@@ -23,6 +23,8 @@ mruby now supports pattern matching (case/in) syntax:
 - Trailing comma in method definition parameters: `def foo(a, b,)` ([f78334b](https://github.com/mruby/mruby/commit/f78334b))
 - Array/Hash/String subclasses can now override `[]` and `[]=` methods ([#6675](https://github.com/mruby/mruby/pull/6675))
 - `OP_SETIDX` optimization for Array and Hash ([ddd8fe1](https://github.com/mruby/mruby/commit/ddd8fe1))
 - `case`/`in` without `else` now raises `NoMatchingPatternError` ([d8de35b](https://github.com/mruby/mruby/commit/d8de35b))
 - Allow compound statement in parenthesized argument context ([919cbd8](https://github.com/mruby/mruby/commit/919cbd8))
 # Changes in C API
@@ -37,6 +39,8 @@ mruby now supports pattern matching (case/in) syntax:
 - `mrb_open()` returns mrb_state with exc set on init failure ([05ffe0c](https://github.com/mruby/mruby/commit/05ffe0c))
 - `mrb_utf8_to_buf()` for UTF-8 encoding consolidation ([7e28e68](https://github.com/mruby/mruby/commit/7e28e68))
 - `kh_is_end()` macro for safe khash iteration ([893cc75](https://github.com/mruby/mruby/commit/893cc75))
 - `mrb_bigint_p()` always defined regardless of bigint gem presence ([6c4a8c0](https://github.com/mruby/mruby/commit/6c4a8c0))
 - `RInteger` and `RFloat` added to `RVALUE` union ([13dbca0](https://github.com/mruby/mruby/commit/13dbca0))
 # ROM Method Tables
@@ -76,6 +80,7 @@ mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 - Emscripten: use native WASM exception handling ([ca364e3](https://github.com/mruby/mruby/commit/ca364e3))
 - HAL (Hardware Abstraction Layer) for platform abstraction in mruby-io, mruby-socket, mruby-dir, mruby-task ([74ca22f](https://github.com/mruby/mruby/commit/74ca22f))
 - `MRUBY_MIRB_READLINE` environment variable to control readline library selection ([0aafb83](https://github.com/mruby/mruby/commit/0aafb83))
 - MSYS2 drive letter support in build script ([77f6ffe](https://github.com/mruby/mruby/commit/77f6ffe))
 - Inter-gem headers separated from external API headers ([#6671](https://github.com/mruby/mruby/pull/6671))
 # Changes in mrbgems
@@ -110,6 +115,7 @@ mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 ## Other Gem Changes
 - **_NOTE_**: `Hash#deconstruct_keys` removed for CRuby compatibility ([34b9412](https://github.com/mruby/mruby/commit/34b9412))
 - **mruby-enum-lazy**: Fix `Lazy#flat_map` to handle non-enumerable block return values ([#6765](https://github.com/mruby/mruby/pull/6765))
 - **mruby-array-ext**: Add `Array#find` and `Array#rfind` methods
 - **mruby-io**: Add `IO#putc` and `Kernel#putc` ([baff6e6](https://github.com/mruby/mruby/commit/baff6e6))
 - **mruby-random**: Replace xoshiro with PCG for better memory efficiency ([f1bab01](https://github.com/mruby/mruby/commit/f1bab01))
@@ -125,6 +131,8 @@ mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 - Optimized masgn to generate literals directly into target registers ([fb5d966](https://github.com/mruby/mruby/commit/fb5d966))
 - Optimized splat of literal arrays in args/literals ([1cb8d73](https://github.com/mruby/mruby/commit/1cb8d73))
 - Early termination after too many parse errors ([510ebd7](https://github.com/mruby/mruby/commit/510ebd7))
 - Chunk array literals at 64 elements to reduce register pressure ([f98d641](https://github.com/mruby/mruby/commit/f98d641))
 - Chunk `%w()` and `%i()` literals to reduce register pressure ([62cf0dc](https://github.com/mruby/mruby/commit/62cf0dc))
 # VM Optimizations
@@ -185,6 +193,10 @@ Other optimizations:
 - [#6705](https://github.com/mruby/mruby/issues/6705) Can't get outer class of an object in C
 - [#6713](https://github.com/mruby/mruby/issues/6713) mruby-polarssl not work
 - [#6720](https://github.com/mruby/mruby/issues/6720) Random float range: different behavior from CRuby
 - [#6722](https://github.com/mruby/mruby/issues/6722) RBreak size overflow on 32-bit platforms with MRB_NO_BOXING
 - [#6740](https://github.com/mruby/mruby/issues/6740) `%w()`/`%i()` register pressure with large literals
 - [#6741](https://github.com/mruby/mruby/issues/6741) `case`/`in` without `else` should raise `NoMatchingPatternError`
 - [#6760](https://github.com/mruby/mruby/issues/6760) `mrb_gc_unregister()` not removing all matching entries
 # Merged Pull Requests
@@ -260,6 +272,7 @@ Other optimizations:
 - [#6589](https://github.com/mruby/mruby/pull/6589) Add pre-commit hook `check-zip-file-is-not-committed`
 - [#6591](https://github.com/mruby/mruby/pull/6591) mruby-eval fix license link in README
 - [#6593](https://github.com/mruby/mruby/pull/6593) README: Add Contributors Avatars, Star History, Table of Contents
 - [#6598](https://github.com/mruby/mruby/pull/6598) Fix heap buffer overflow in `#method_missing`
 - [#6599](https://github.com/mruby/mruby/pull/6599) pre-commit: run `markdown-link-check`, `oxipng`, `prettier` manually
 - [#6600](https://github.com/mruby/mruby/pull/6600) `dreamcast_shelf build config`: update to use KallistiOS wrappers
 - [#6601](https://github.com/mruby/mruby/pull/6601) fix: skip local build_config.rb when working in MRUBY_ROOT
@@ -303,6 +316,33 @@ Other optimizations:
 - [#6716](https://github.com/mruby/mruby/pull/6716) Fixes identity for proc object
 - [#6717](https://github.com/mruby/mruby/pull/6717) Fix mruby-task: wrapping by critical section and setting initial task receiver
 - [#6718](https://github.com/mruby/mruby/pull/6718) Add installation instructions for conda and Homebrew
 - [#6723](https://github.com/mruby/mruby/pull/6723) Add `RInteger` and `RFloat` to `RVALUE`
 - [#6727](https://github.com/mruby/mruby/pull/6727) Language documentation: update wording of "overloading" section
 - [#6729](https://github.com/mruby/mruby/pull/6729) Simplifying dependency addition for gensym task
 - [#6730](https://github.com/mruby/mruby/pull/6730) Simplifying presym file generation actions
 - [#6733](https://github.com/mruby/mruby/pull/6733) Include `mruby/presym.h` for all source files
 - [#6734](https://github.com/mruby/mruby/pull/6734) Chunk array literals at 64 elements to reduce register pressure
 - [#6735](https://github.com/mruby/mruby/pull/6735) Prevent full recompilation without changes to presym file
 - [#6739](https://github.com/mruby/mruby/pull/6739) Fix MSYS2 build error with drive letters
 - [#6743](https://github.com/mruby/mruby/pull/6743) Chunk `%w()` and `%i()` literals to reduce register pressure
 - [#6744](https://github.com/mruby/mruby/pull/6744) Raise `NoMatchingPatternError` in `case`/`in` without `else`
 - [#6747](https://github.com/mruby/mruby/pull/6747) Correctly handle empty hash as default named argument
 - [#6749](https://github.com/mruby/mruby/pull/6749) Fix microcontroller profile
 - [#6750](https://github.com/mruby/mruby/pull/6750) Fix out-of-bounds read and divide-by-zero in `Array#product`
 - [#6752](https://github.com/mruby/mruby/pull/6752) Fix `attr_reader`-generated methods accepting extra arguments
 - [#6753](https://github.com/mruby/mruby/pull/6753) Further optimize `Array#product`
 - [#6754](https://github.com/mruby/mruby/pull/6754) Mark `attr_reader` procs as noarg
 - [#6755](https://github.com/mruby/mruby/pull/6755) Reload `ci` after `mrb_hash_delete_key()` in keyword argument handling
 - [#6756](https://github.com/mruby/mruby/pull/6756) Avoid impact of object modifications caused by `mrb_vm_exec()` calls
 - [#6758](https://github.com/mruby/mruby/pull/6758) Don't assign result of `mrb_funcall()` directly to `regs`
 - [#6759](https://github.com/mruby/mruby/pull/6759) Define `mrb_bigint_p()` always
 - [#6761](https://github.com/mruby/mruby/pull/6761) Fix `mrb_gc_unregister()` to remove all matching entries
 - [#6762](https://github.com/mruby/mruby/pull/6762) Write generated test C files atomically to avoid build race condition
 - [#6765](https://github.com/mruby/mruby/pull/6765) Fix `Lazy#flat_map` to handle non-enumerable block return values
 - [#6767](https://github.com/mruby/mruby/pull/6767) Allow compound statement in parenthesized argument context
 - [#6780](https://github.com/mruby/mruby/pull/6780) Fix `String#prepend` with self-referencing arguments
 - [#6781](https://github.com/mruby/mruby/pull/6781) Protect `sprintf` format string from mutation during callbacks
 - [#6783](https://github.com/mruby/mruby/pull/6783) Pin GitHub Actions workflows to commit hashes
 # Security Fixes
@@ -320,4 +360,8 @@ Other optimizations:
 - Heap-use-after-free in insertion_sort ([099d2c47](https://github.com/mruby/mruby/commit/099d2c47))
 - Integer overflow in str_check_length ([6afff1c3](https://github.com/mruby/mruby/commit/6afff1c3))
 - Integer overflow in Integer#lcm ([070bef24](https://github.com/mruby/mruby/commit/070bef24))
 - Heap buffer overflow in `#method_missing` ([550d10a](https://github.com/mruby/mruby/commit/550d10a))
 - Out-of-bounds read and divide-by-zero in `Array#product` ([8441eaf](https://github.com/mruby/mruby/commit/8441eaf))
 - Heap buffer overflow in `String#prepend` with self-referencing arguments ([18ba026](https://github.com/mruby/mruby/commit/18ba026))
 - Use-after-free in `sprintf` via `to_s` callback mutating format string ([48fc422](https://github.com/mruby/mruby/commit/48fc422))
 - Multiple memory leak fixes in bigint, Set, Array, and Task gems
@@ -51,6 +51,8 @@ To get mruby, you can download the stable version 4.0.0 from the official mruby
 GitHub repository or clone the trunk of the mruby source tree with the "git
 clone" command. You can also install and compile mruby using [ruby-install](https://github.com/postmodern/ruby-install), [ruby-build](https://github.com/rbenv/ruby-build), [rvm](https://github.com/rvm/rvm), [conda](https://anaconda.org/channels/conda-forge/packages/mruby/overview) or [Homebrew](https://formulae.brew.sh/formula/mruby).
 The release candidate version 4.0.0 of mruby can be downloaded via the following URL: [https://github.com/mruby/mruby/archive/4.0.0-rc3.zip](https://github.com/mruby/mruby/archive/4.0.0-rc3.zip)
 The latest development version of mruby can be downloaded via the following URL: [https://github.com/mruby/mruby/zipball/master](https://github.com/mruby/mruby/zipball/master)
 The trunk of the mruby source tree can be checked out with the
@@ -292,9 +292,7 @@ class Scene
        r = rad.x / nsfs
        g = rad.y / nsfs
        b = rad.z / nsfs
-        printf("%c", clamp(r))
+        print([clamp(r), clamp(g), clamp(b)].pack("CCC"))
        printf("%c", clamp(g))
        printf("%c", clamp(b))
      end
    end
  end
@@ -303,7 +301,7 @@ end
 # File.open("ao.ppm", "w") do |fp|
  printf("P6\n")
  printf("%d %d\n", IMAGE_WIDTH, IMAGE_HEIGHT)
-  printf("255\n", IMAGE_WIDTH, IMAGE_HEIGHT)
+  printf("255\n")
  Scene.new.render(IMAGE_WIDTH, IMAGE_HEIGHT, NSUBSAMPLES)
 #  Scene.new.render(256, 256, 2)
 # end
@@ -30,7 +30,7 @@ MRuby::CrossBuild.new("ArduinoDue") do |conf|
    #configuration for low memory environment
    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
-    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(KHASH_INITIAL_SIZE=8)
    cc.defines << %w(MRB_GC_STRESS)
    #cc.defines << %w(MRB_NO_STDIO) #if you don't need stdio.
    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
@@ -16,7 +16,7 @@ MRuby::CrossBuild.new("RX630") do |conf|
    #configuration for low memory environment
    cc.defines << %w(MRB_USE_FLOAT32)
    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
-    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(KHASH_INITIAL_SIZE=8)
    cc.defines << %w(MRB_GC_STRESS)
    cc.defines << %w(MRB_NO_STDIO) #if you don't need stdio.
    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
@@ -27,7 +27,7 @@ MRuby::CrossBuild.new("chipKITMax32") do |conf|
    #configuration for low memory environment
    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
-    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(KHASH_INITIAL_SIZE=8)
    cc.defines << %w(MRB_GC_STRESS)
    #cc.defines << %w(MRB_NO_STDIO) #if you don't need stdio.
    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
@@ -64,10 +64,8 @@ MRuby::Build.new do |conf|
  # APE binaries use .com extension
  conf.exts.executable = '.com'
-  # Cosmopolitan provides POSIX compatibility, explicitly select POSIX HALs
+  # Cosmopolitan provides POSIX compatibility
-  conf.gem core: 'hal-posix-io'
+  conf.ports :posix
  conf.gem core: 'hal-posix-socket'
  conf.gem core: 'hal-posix-dir'
  # Standard library
  conf.gembox 'stdlib'
@@ -0,0 +1,88 @@
 MRuby::Build.new do |conf|
  # load specific toolchain settings
  conf.toolchain
  # Use mrbgems
  # conf.gem 'examples/mrbgems/ruby_extension_example'
  # conf.gem 'examples/mrbgems/c_extension_example' do |g|
  #   g.cc.flags << '-g' # append cflags in this gem
  # end
  # conf.gem 'examples/mrbgems/c_and_ruby_extension_example'
  # conf.gem :core => 'mruby-eval'
  # conf.gem :mgem => 'mruby-onig-regexp'
  # conf.gem :github => 'mattn/mruby-onig-regexp'
  # conf.gem :git => 'git@github.com:mattn/mruby-onig-regexp.git', :branch => 'master', :options => '-v'
  # include the GEM box
  #conf.gembox 'default'
  # C compiler settings
  # conf.cc do |cc|
  #   cc.command = ENV['CC'] || 'gcc'
  #   cc.flags = [ENV['CFLAGS'] || %w()]
  #   cc.include_paths = ["#{root}/include"]
  #   cc.defines = %w()
  #   cc.option_include_path = %q[-I"%s"]
  #   cc.option_define = '-D%s'
  #   cc.compile_options = %Q[%{flags} -MMD -o "%{outfile}" -c "%{infile}"]
  # end
  # mrbc settings
  # conf.mrbc do |mrbc|
  #   mrbc.compile_options = "-g -B%{funcname} -o-" # The -g option is required for line numbers
  # end
  # Linker settings
  # conf.linker do |linker|
  #   linker.command = ENV['LD'] || 'gcc'
  #   linker.flags = [ENV['LDFLAGS'] || []]
  #   linker.flags_before_libraries = []
  #   linker.libraries = %w()
  #   linker.flags_after_libraries = []
  #   linker.library_paths = []
  #   linker.option_library = '-l%s'
  #   linker.option_library_path = '-L%s'
  #   linker.link_options = %Q[%{flags} -o "%{outfile}" %{objs} %{libs}]
  # end
  # Archiver settings
  # conf.archiver do |archiver|
  #   archiver.command = ENV['AR'] || 'ar'
  #   archiver.archive_options = 'rs "%{outfile}" %{objs}'
  # end
  # Parser generator settings
  # conf.yacc do |yacc|
  #   yacc.command = ENV['YACC'] || 'bison'
  #   yacc.compile_options = %q[-o "%{outfile}" "%{infile}"]
  # end
  # gperf settings
  # conf.gperf do |gperf|
  #   gperf.command = 'gperf'
  #   gperf.compile_options = %q[-L ANSI-C -C -j1 -i 1 -o -t -N mrb_reserved_word -k"1,3,$" "%{infile}" > "%{outfile}"]
  # end
  # file extensions
  # conf.exts do |exts|
  #   exts.object = '.o'
  #   exts.executable = '' # '.exe' if Windows
  #   exts.library = '.a'
  # end
  # file separator
  # conf.file_separator = '/'
  # change library directory name from the default "lib" if necessary
  # conf.libdir_name = 'lib64'
  # Turn on `enable_debug` for better debugging
  conf.enable_sanitizer 'address,undefined'
  conf.enable_debug
  conf.enable_bintest
  conf.enable_test
  conf.ports :glib
  conf.cc.defines << 'MRB_TASK_BUILD_DEMO'
  conf.gem core: 'mruby-task'
  conf.gem core: 'mruby-compiler'
 end
@@ -1,4 +1,4 @@
-MRuby::Build.new do |conf|
+MRuby::Build.new('host-cxx') do |conf|
  conf.toolchain
  # include the default GEMs
@@ -13,6 +13,8 @@ MRuby::Build.new('host') do |conf|
  # Generate mruby debugger command (require mruby-eval)
  conf.gem :core => "mruby-bin-debugger"
  # Regexp is included via stdlib.gembox
  # test
  conf.enable_test
  # bintest
@@ -1,36 +1,94 @@
-# NOTE: Currently, this configuration file does not support VisualC++!
+# Build mruby with a shared libmruby.so (in addition to the usual
-#       Your help is needed!
+# libmruby.a / executables).
 #
 # Produces (in build/host/lib/):
 #   libmruby.a              the static archive (as in the default build)
 #   libmruby.so             the shared library, with SONAME=libmruby.so.<MAJOR>.<MINOR>
 #   libmruby.so.<MAJOR>.<MINOR>  symlink to libmruby.so (matches SONAME)
 #   libmruby.map            linker version script (MRUBY_<RELEASE_NO>)
 #
 # Also produces the matching libmruby_core.so + symlink for completeness.
 #
 # Symbol versioning ties to MRUBY_RELEASE_NO (e.g. MRUBY_40000 for 4.0.0).
 # mruby has historically had ABI breaks between TEENY versions, so the
 # version tag uses the full release number rather than just MAJOR.MINOR.
 #
 # The shared library is built FROM the static archive via
 # `-Wl,--whole-archive`, so the existing static-build pipeline (including
 # the test infrastructure) is unaffected.  Executables in build/host/bin
 # remain statically linked; distros that want dynamically-linked
 # executables can rebuild them against the .so.
 #
 # NOTE: gcc/clang only — VisualC++ support requires a separate config.
 require "mruby/source"
 MRuby::Build.new do |conf|
  # load specific toolchain settings
  conf.toolchain
  # include the GEM box
  conf.gembox 'default'
-  # C compiler settings
+  # -fPIC so the static archive's contents can be linked into the .so.
  conf.compilers.each do |cc|
    cc.flags << '-fPIC'
  end
  conf.archiver do |archiver|
    archiver.command = cc.command
    archiver.archive_options = '-shared -o %{outfile} %{objs}'
  end
  # file extensions
  conf.exts do |exts|
    exts.library = '.so'
  end
  # file separator
  # conf.file_separator = '/'
  # enable this if better compatibility with C++ is desired
  #conf.enable_cxx_exception
  # Turn on `enable_debug` for better debugging
  conf.enable_debug
  conf.enable_bintest
  conf.enable_test
 end
 # Add the shared-library targets as a post-build pass, so the default
 # static-build pipeline remains untouched.
 MRuby.each_target do
  next unless name == "host"
  libdir = File.join(build_dir, libdir_name)
  vermap = File.join(build_dir, "libmruby.map")
  vertag = "MRUBY_#{MRuby::Source::MRUBY_RELEASE_NO}"
  # Generate the version script eagerly — it has no .o dependencies and is
  # tiny enough that lazy generation isn't worth the rake plumbing.
  mkdir_p File.dirname(vermap)
  File.write(vermap, <<~MAP)
    #{vertag} {
      global: *;
      local:  *;
    };
  MAP
  major = MRuby::Source::MRUBY_RELEASE_MAJOR
  minor = MRuby::Source::MRUBY_RELEASE_MINOR
  [
    [libmruby_static,      "libmruby"],
    [libmruby_core_static, "libmruby_core"],
  ].each do |archive, basename|
    so      = File.join(libdir, "#{basename}.so")
    symlink = "#{so}.#{major}.#{minor}"
    soname  = "#{basename}.so.#{major}.#{minor}"
    # Build .so from the static archive via --whole-archive.
    file so => [archive, vermap] do |t|
      _pp "LD", so.relative_path
      sh "#{cc.command} -shared -fPIC -o #{so}" \
         " -Wl,-soname,#{soname}" \
         " -Wl,--version-script=#{vermap}" \
         " -Wl,--whole-archive #{archive} -Wl,--no-whole-archive" \
         " -lm"
    end
    products << so
    # SONAME-matching symlink: needed so executables linked with -lmruby
    # (which embeds the SONAME as DT_NEEDED) can find the library at
    # runtime via standard search paths.
    file symlink => so do |t|
      _pp "LN", "#{symlink.relative_path} -> #{File.basename(so)}"
      rm_f symlink
      File.symlink(File.basename(so), symlink)
    end
    products << symlink
  end
 end
@@ -72,7 +72,9 @@ MRuby::CrossBuild.new("playstationportable") do |conf|
  conf.gem :core => "mruby-os-memsize"
  conf.gem :core => "mruby-proc-binding"
  conf.gem :core => "mruby-sleep"
-  conf.gem :core => "mruby-io"
+  # Disabled until PSP-specific HALs are available; the POSIX HALs depend on
-  conf.gem :core => "mruby-dir"
+  # APIs that the PSP SDK does not fully provide.
-  #conf.gem :core => "mruby-socket" unsupported
+  # conf.gem :core => "mruby-io"
  # conf.gem :core => "mruby-dir"
  # conf.gem :core => "mruby-socket"
 end
@@ -4,44 +4,44 @@
 New to mruby? Start here:
-| Document | Description |
+| Document                                     | Description                            |
-| -------- | ----------- |
+| -------------------------------------------- | -------------------------------------- |
 | [Getting Started](guides/getting-started.md) | Build mruby and run your first program |
-| [Language Features](guides/language.md) | Ruby subset supported by mruby |
+| [Language Features](guides/language.md)      | Ruby subset supported by mruby         |
-| [Limitations](limitations.md) | Behavioral differences from CRuby |
+| [Limitations](limitations.md)                | Behavioral differences from CRuby      |
 ## Guides (for embedders and gem authors)
 ### Embedding mruby in C
-| Document | Description |
+| Document                                | Description                                      |
-| -------- | ----------- |
+| --------------------------------------- | ------------------------------------------------ |
-| [C API Reference](guides/capi.md) | Values, classes, methods, error handling, fibers |
+| [C API Reference](guides/capi.md)       | Values, classes, methods, error handling, fibers |
-| [GC Arena](guides/gc-arena-howto.md) | Managing temporary objects in C extensions |
+| [GC Arena](guides/gc-arena-howto.md)    | Managing temporary objects in C extensions       |
-| [Linking](guides/link.md) | Linking with `libmruby` |
+| [Linking](guides/link.md)               | Linking with `libmruby`                          |
-| [Amalgamation](guides/amalgamation.md) | Single-file build for easy integration |
+| [Amalgamation](guides/amalgamation.md)  | Single-file build for easy integration           |
-| [Precompiled Symbols](guides/symbol.md) | Compile-time symbol allocation |
+| [Precompiled Symbols](guides/symbol.md) | Compile-time symbol allocation                   |
 ### Building and Configuring
-| Document | Description |
+| Document                                 | Description                                 |
-| -------- | ----------- |
+| ---------------------------------------- | ------------------------------------------- |
-| [Compilation](guides/compile.md) | Build system, cross-compilation, toolchains |
+| [Compilation](guides/compile.md)         | Build system, cross-compilation, toolchains |
-| [Build Configuration](guides/mrbconf.md) | Compile-time macros (`MRB_*` flags) |
+| [Build Configuration](guides/mrbconf.md) | Compile-time macros (`MRB_*` flags)         |
-| [mrbgems](guides/mrbgems.md) | Creating and managing gems |
+| [mrbgems](guides/mrbgems.md)             | Creating and managing gems                  |
-| [Memory](guides/memory.md) | Allocator customization and heap regions |
+| [Memory](guides/memory.md)               | Allocator customization and heap regions    |
 ### Tools
-| Document | Description |
+| Document                                        | Description                                     |
-| -------- | ----------- |
+| ----------------------------------------------- | ----------------------------------------------- |
-| [Debugger](guides/debugger.md) | Using `mrdb` for debugging |
+| [Debugger](guides/debugger.md)                  | Using `mrdb` for debugging                      |
 | [ROM Method Tables](guides/rom-method-table.md) | Read-only method tables for constrained devices |
 ### Reference
-| Document | Description |
+| Document                              | Description        |
-| -------- | ----------- |
+| ------------------------------------- | ------------------ |
 | [Directory Structure](guides/hier.md) | Source tree layout |
 ## Internals (for mruby contributors)
@@ -49,14 +49,14 @@ New to mruby? Start here:
 Start with [Architecture](internal/architecture.md) for an overview,
 then dive into the subsystem you need:
-| Document | Description |
+| Document                                  | Description                                        |
-| -------- | ----------- |
+| ----------------------------------------- | -------------------------------------------------- |
-| [Architecture](internal/architecture.md) | Overview of object model, VM, GC, compiler |
+| [Architecture](internal/architecture.md)  | Overview of object model, VM, GC, compiler         |
-| [Virtual Machine](internal/vm.md) | Dispatch loop, call frames, method lookup, fibers |
+| [Virtual Machine](internal/vm.md)         | Dispatch loop, call frames, method lookup, fibers  |
-| [Garbage Collector](internal/gc.md) | Tri-color marking, write barriers, generational GC |
+| [Garbage Collector](internal/gc.md)       | Tri-color marking, write barriers, generational GC |
-| [Compiler Pipeline](internal/compiler.md) | Parser, code generator, IRep, binary format |
+| [Compiler Pipeline](internal/compiler.md) | Parser, code generator, IRep, binary format        |
-| [Opcodes](internal/opcode.md) | VM instruction set reference |
+| [Opcodes](internal/opcode.md)             | VM instruction set reference                       |
-| [Value Boxing](internal/boxing.md) | How `mrb_value` encodes types |
+| [Value Boxing](internal/boxing.md)        | How `mrb_value` encodes types                      |
 ## Release Notes
@@ -73,14 +73,14 @@ The following gems work with amalgamation:
 - `mruby-enum-ext`, `mruby-compar-ext`
 - `mruby-error`, `mruby-math`, `mruby-struct`
 - `mruby-bigint`, `mruby-rational`, `mruby-complex`
- `mruby-io` (with `hal-posix-io`)
+- `mruby-io` (with the active `ports/<name>/` HAL)
- `mruby-task` (with `hal-posix-task`)
+- `mruby-task` (with the active `ports/<name>/` HAL)
 ### Platform-Dependent Gems
 Gems that use a HAL (Hardware Abstraction Layer) include
 platform-specific code in the amalgamation. For example, if
-`mruby-io` selects `hal-posix-io` on Linux, the generated `mruby.c`
+`mruby-io` selects its POSIX port on Linux, the generated `mruby.c`
 contains POSIX-specific code and cannot be compiled on Windows.
 If you need amalgamated files for multiple platforms, generate them
@@ -381,6 +381,13 @@ mrb_define_method(mrb, point, "initialize", point_init, MRB_ARGS_REQ(2));
 mrb_define_method(mrb, point, "x", point_x, MRB_ARGS_NONE());
 ```
 **Do not call into mruby from a `dfree` handler.** The handler runs
 from inside GC sweep; allocating Ruby objects, calling
 `mrb_funcall`, `mrb_yield`, raising exceptions, or otherwise
 re-entering the VM can trigger a recursive GC that revisits the
 same object and causes double-free. Keep `dfree` to `mrb_free` /
 plain C cleanup of the wrapped data only.
 ## Exception Handling
 ### Raising Exceptions
@@ -40,7 +40,7 @@ To confirm mrdb was installed properly, run mrdb with the `--version` option:
 ```bash
 $ mrdb --version
-mruby 3.4.0 (2025-04-20)
+mruby 4.0.0 (2026-04-20)
 ```
 ## 2.2 Basic Operation
@@ -205,11 +205,11 @@ mruby's numeric type sizes depend on the boxing mode and platform.
 ### Integer
-| Configuration | Range |
+| Configuration                          | Range            |
-| ------------- | ----- |
+| -------------------------------------- | ---------------- |
 | 64-bit word boxing (default on 64-bit) | roughly +/- 2^62 |
 | 32-bit word boxing (default on 32-bit) | roughly +/- 2^30 |
-| NaN boxing (64-bit only) | -2^31 to 2^31-1 |
+| NaN boxing (64-bit only)               | -2^31 to 2^31-1  |
 Integer overflow raises a `RangeError` unless the `mruby-bigint` gem
 is included, in which case integers automatically promote to
@@ -235,32 +235,32 @@ With word boxing on 64-bit, many float values are stored inline
 These classes are always available in mruby (no gem required):
-| Class | Notes |
+| Class         | Notes                                  |
-| ----- | ----- |
+| ------------- | -------------------------------------- |
-| Object | Base class for all objects |
+| Object        | Base class for all objects             |
-| Module | Module definition and mixin |
+| Module        | Module definition and mixin            |
-| Class | Class definition and instantiation |
+| Class         | Class definition and instantiation     |
-| NilClass | Singleton `nil` |
+| NilClass      | Singleton `nil`                        |
-| TrueClass | Singleton `true` |
+| TrueClass     | Singleton `true`                       |
-| FalseClass | Singleton `false` |
+| FalseClass    | Singleton `false`                      |
-| Integer | Fixed-precision integer |
+| Integer       | Fixed-precision integer                |
-| Float | Floating-point (unless `MRB_NO_FLOAT`) |
+| Float         | Floating-point (unless `MRB_NO_FLOAT`) |
-| Symbol | Interned identifier |
+| Symbol        | Interned identifier                    |
-| String | Mutable byte string |
+| String        | Mutable byte string                    |
-| Array | Ordered collection |
+| Array         | Ordered collection                     |
-| Hash | Key-value mapping |
+| Hash          | Key-value mapping                      |
-| Range | Interval representation |
+| Range         | Interval representation                |
-| Proc | Closure / callable object |
+| Proc          | Closure / callable object              |
-| Exception | Exception hierarchy root |
+| Exception     | Exception hierarchy root               |
-| StandardError | Common error base |
+| StandardError | Common error base                      |
 ### Core Modules
-| Module | Notes |
+| Module     | Notes                                     |
-| ------ | ----- |
+| ---------- | ----------------------------------------- |
-| Kernel | Core methods (`puts`, `p`, `raise`, etc.) |
+| Kernel     | Core methods (`puts`, `p`, `raise`, etc.) |
-| Comparable | Comparison operators via `<=>` |
+| Comparable | Comparison operators via `<=>`            |
-| Enumerable | Collection iteration methods |
+| Enumerable | Collection iteration methods              |
 ## Standard Library (via gemboxes)
@@ -270,70 +270,70 @@ gembox provides the class or feature you need:
 ### Classes and Modules
-| Class/Module | Gembox | Gem |
+| Class/Module          | Gembox     | Gem               |
-| ------------ | ------ | --- |
+| --------------------- | ---------- | ----------------- |
-| Fiber | stdlib | mruby-fiber |
+| Fiber                 | stdlib     | mruby-fiber       |
-| Enumerator | stdlib | mruby-enumerator |
+| Enumerator            | stdlib     | mruby-enumerator  |
-| Enumerator::Lazy | stdlib | mruby-enum-lazy |
+| Enumerator::Lazy      | stdlib     | mruby-enum-lazy   |
-| Set | stdlib | mruby-set |
+| Set                   | stdlib     | mruby-set         |
-| ObjectSpace | stdlib | mruby-objectspace |
+| ObjectSpace           | stdlib     | mruby-objectspace |
-| Time | stdlib-ext | mruby-time |
+| Time                  | stdlib-ext | mruby-time        |
-| Struct | stdlib-ext | mruby-struct |
+| Struct                | stdlib-ext | mruby-struct      |
-| Data | stdlib-ext | mruby-data |
+| Data                  | stdlib-ext | mruby-data        |
-| Random | stdlib-ext | mruby-random |
+| Random                | stdlib-ext | mruby-random      |
-| IO, File | stdlib-io | mruby-io |
+| IO, File              | stdlib-io  | mruby-io          |
-| Socket | stdlib-io | mruby-socket |
+| Socket                | stdlib-io  | mruby-socket      |
-| Dir | stdlib-io | mruby-dir |
+| Dir                   | stdlib-io  | mruby-dir         |
-| Errno | stdlib-io | mruby-errno |
+| Errno                 | stdlib-io  | mruby-errno       |
-| Math | math | mruby-math |
+| Math                  | math       | mruby-math        |
-| Rational | math | mruby-rational |
+| Rational              | math       | mruby-rational    |
-| Complex | math | mruby-complex |
+| Complex               | math       | mruby-complex     |
-| Bigint | math | mruby-bigint |
+| Bigint                | math       | mruby-bigint      |
-| Method, UnboundMethod | metaprog | mruby-method |
+| Method, UnboundMethod | metaprog   | mruby-method      |
 ### Methods and Features
-| Feature | Gembox | Gem |
+| Feature                       | Gembox     | Gem                |
-| ------- | ------ | --- |
+| ----------------------------- | ---------- | ------------------ |
-| `catch`/`throw` | stdlib | mruby-catch |
+| `catch`/`throw`               | stdlib     | mruby-catch        |
-| `Kernel#sprintf`, `String#%` | stdlib-ext | mruby-sprintf |
+| `Kernel#sprintf`, `String#%`  | stdlib-ext | mruby-sprintf      |
-| `Array#pack`, `String#unpack` | stdlib-ext | mruby-pack |
+| `Array#pack`, `String#unpack` | stdlib-ext | mruby-pack         |
-| `Kernel#rand` | stdlib-ext | mruby-random |
+| `Kernel#rand`                 | stdlib-ext | mruby-random       |
-| `Kernel#eval` | metaprog | mruby-eval |
+| `Kernel#eval`                 | metaprog   | mruby-eval         |
-| `Kernel#binding` | metaprog | mruby-binding |
+| `Kernel#binding`              | metaprog   | mruby-binding      |
-| `Proc#binding` | metaprog | mruby-proc-binding |
+| `Proc#binding`                | metaprog   | mruby-proc-binding |
-| Runtime compiler | metaprog | mruby-compiler |
+| Runtime compiler              | metaprog   | mruby-compiler     |
 ### Core Class Extensions
 The `stdlib` gembox also extends built-in classes with additional
 methods. These are included by default:
-| Extension | Examples |
+| Extension               | Examples                                       |
-| --------- | -------- |
+| ----------------------- | ---------------------------------------------- |
-| Array extensions | `#dig`, `#union`, `#difference` |
+| Array extensions        | `#dig`, `#union`, `#difference`                |
-| Hash extensions | `#dig`, `#transform_keys`, `#transform_values` |
+| Hash extensions         | `#dig`, `#transform_keys`, `#transform_values` |
-| String extensions | `#encode`, `#bytes`, `#chars` |
+| String extensions       | `#encode`, `#bytes`, `#chars`                  |
-| Numeric extensions | `Integer#digits`, `Integer#pow` |
+| Numeric extensions      | `Integer#digits`, `Integer#pow`                |
-| Comparable extensions | `#clamp` |
+| Comparable extensions   | `#clamp`                                       |
-| Enumerable extensions | `#sort_by`, `#min_by`, `#max_by`, `#tally` |
+| Enumerable extensions   | `#sort_by`, `#min_by`, `#max_by`, `#tally`     |
-| Range extensions | `#size`, `#cover?` |
+| Range extensions        | `#size`, `#cover?`                             |
-| Proc extensions | `#<<`, `#>>` (composition) |
+| Proc extensions         | `#<<`, `#>>` (composition)                     |
-| Symbol extensions | `#to_proc` |
+| Symbol extensions       | `#to_proc`                                     |
-| Object extensions | `#then`, `#yield_self` |
+| Object extensions       | `#then`, `#yield_self`                         |
-| Kernel extensions | `#__method__` |
+| Kernel extensions       | `#__method__`                                  |
-| Class/Module extensions | `Module#name` |
+| Class/Module extensions | `Module#name`                                  |
 ### Gembox Summary
-| Gembox | Contents | Notes |
+| Gembox       | Contents                                      | Notes                                        |
-| ------ | -------- | ----- |
+| ------------ | --------------------------------------------- | -------------------------------------------- |
-| `stdlib` | Core class extensions, Fiber, Enumerator, Set | Works with `MRB_NO_STDIO` and `MRB_NO_FLOAT` |
+| `stdlib`     | Core class extensions, Fiber, Enumerator, Set | Works with `MRB_NO_STDIO` and `MRB_NO_FLOAT` |
-| `stdlib-ext` | Time, Struct, Data, Random, sprintf, pack | Works with `MRB_NO_STDIO` and `MRB_NO_FLOAT` |
+| `stdlib-ext` | Time, Struct, Data, Random, sprintf, pack     | Works with `MRB_NO_STDIO` and `MRB_NO_FLOAT` |
-| `stdlib-io` | IO, File, Dir, Socket, Errno | Requires stdio |
+| `stdlib-io`  | IO, File, Dir, Socket, Errno                  | Requires stdio                               |
-| `math` | Math, Rational, Complex, Bigint | Works with `MRB_NO_STDIO` |
+| `math`       | Math, Rational, Complex, Bigint               | Works with `MRB_NO_STDIO`                    |
-| `metaprog` | eval, binding, Method, compiler | Works with `MRB_NO_STDIO` and `MRB_NO_FLOAT` |
+| `metaprog`   | eval, binding, Method, compiler               | Works with `MRB_NO_STDIO` and `MRB_NO_FLOAT` |
-| `default` | All of the above + CLI tools | Full installation |
+| `default`    | All of the above + CLI tools                  | Full installation                            |
 ## Key Differences from CRuby
@@ -416,15 +416,15 @@ differently on 32-bit or NaN boxing configurations.
 Key compile-time macros that affect language behavior:
-| Macro | Effect |
+| Macro                | Effect                             |
-| ----- | ------ |
+| -------------------- | ---------------------------------- |
-| `MRB_NO_FLOAT` | Remove all float support |
+| `MRB_NO_FLOAT`       | Remove all float support           |
-| `MRB_USE_FLOAT32` | Use 32-bit float instead of double |
+| `MRB_USE_FLOAT32`    | Use 32-bit float instead of double |
-| `MRB_UTF8_STRING` | Enable UTF-8 string handling |
+| `MRB_UTF8_STRING`    | Enable UTF-8 string handling       |
-| `MRB_INT32` | Force 32-bit integer |
+| `MRB_INT32`          | Force 32-bit integer               |
-| `MRB_INT64` | Force 64-bit integer |
+| `MRB_INT64`          | Force 64-bit integer               |
-| `MRB_STR_LENGTH_MAX` | Max string length (default 1MB) |
+| `MRB_STR_LENGTH_MAX` | Max string length (default 1MB)    |
-| `MRB_ARY_LENGTH_MAX` | Max array length (default 2^17) |
+| `MRB_ARY_LENGTH_MAX` | Max array length (default 2^17)    |
 See [mrbconf.md](mrbconf.md) for the complete list of configuration
 macros.
@@ -202,10 +202,10 @@ any other heap page. The only differences are:
 The page size is controlled by `MRB_HEAP_PAGE_SIZE` (default: 1024 slots).
 Each page occupies:
-| Platform | Slot size | Page size (approx)  |
+| Platform | Slot size | Page size (approx) |
-|----------|-----------|---------------------|
+| -------- | --------- | ------------------ |
-| 64-bit   | 40 bytes  | ~41 KB              |
+| 64-bit   | 40 bytes  | ~41 KB             |
-| 32-bit   | 24 bytes  | ~25 KB              |
+| 32-bit   | 24 bytes  | ~25 KB             |
 To estimate pages for a given buffer: `pages = buffer_size / sizeof(mrb_heap_page)`.
 Each page provides `MRB_HEAP_PAGE_SIZE` object slots.
@@ -233,10 +233,10 @@ end
 - Specifies 4th argument(`argc`) max value of `mrb_funcall`.
 - Raises `ArgumentError` when the `argc` argument is bigger then this value `mrb_funcall`.
-`KHASH_DEFAULT_SIZE`
+`KHASH_INITIAL_SIZE`
 - Default value is `32`.
- Specifies default size of khash table bucket.
+- Specifies initial size of khash table bucket.
 - Used in `kh_init_ ## name` function.
 `MRB_NO_METHOD_CACHE`
@@ -272,7 +272,7 @@ deployment targets. Define one of the following:
 `MRB_CONSTRAINED_BASELINE_PROFILE`
 - For micro controllers.
- Enables `MRB_NO_METHOD_CACHE`, reduces `KHASH_DEFAULT_SIZE` to `16`,
+- Enables `MRB_NO_METHOD_CACHE`, reduces `KHASH_INITIAL_SIZE` to `16`,
  and `MRB_HEAP_PAGE_SIZE` to `256`.
 `MRB_BASELINE_PROFILE`
@@ -172,6 +172,8 @@ The maximal GEM structure looks like this:
    |
    +- src/             <- Source for C extension
    |
    +- ports/<name>/    <- Platform-specific C sources (see Platform Ports)
    |
    +- tools/           <- Source for Executable (in C)
    |
    +- test/            <- Test code (Ruby)
@@ -182,6 +184,8 @@ contains C/C++ files to extend mruby. The `include` directory contains C/C++ hea
 files. The `test` directory contains C/C++ and pure Ruby files for testing purposes
 which will be used by `mrbtest`. `mrbgem.rake` contains the specification
 to compile C and Ruby files. `README.md` is a short description of your GEM.
 The optional `ports/<name>/` directories hold platform-specific C sources
 selected at build time; see [Platform Ports](#platform-ports-ports) below.
 ## Build process
@@ -332,6 +336,64 @@ end
 **NOTE**: Using the `build_settings` method will cause GEM's all build command settings
 directly written in the block passed to `MRuby::Gem::Specification.new` to be ignored.
 ## Platform Ports (ports/)
 A gem may ship platform-specific C sources under `ports/<name>/`
 subdirectories. The build configuration selects which port name(s)
 are active via `conf.ports`, and each gem compiles the sources of
 the first matching `ports/<name>/` it ships:
 ```ruby
 MRuby::Build.new do |conf|
  conf.toolchain
  conf.ports :posix     # selects ports/posix/ across all gems
 end
 ```
 `conf.ports` accepts multiple names as a fallback chain. Each gem
 picks the first directory in the list that exists on its side:
 ```ruby
 conf.ports :rp2040, :posix    # try rp2040 per-gem, else posix
 ```
 Host builds auto-detect `:posix` or `:win` when `conf.ports` is
 not set. Sources outside `ports/` (i.e. `src/`) are always
 compiled regardless of the port selection.
 ### External HAL Provider Gems
 A third-party gem may replace another gem's bundled port at build
 time. A gem whose name matches `hal-<short>-<conf>` is recognized
 as the external HAL provider for the target gem whose name's last
 `-`-separated segment is `<short>`. For example, `hal-task-glib`
 overrides the HAL of `mruby-task`; `hal-io-uring` would override
 `mruby-io`. The HAL provider must depend on its target so it can
 `#include` the target's HAL header:
 ```ruby
 MRuby::Gem::Specification.new('hal-task-glib') do |spec|
  spec.license = 'MIT'
  spec.author  = 'Your Name'
  spec.summary = 'GLib HAL for mruby-task'
  spec.add_dependency 'mruby-task', core: 'mruby-task'
  # src/ contains the HAL implementation
 end
 ```
 When a matching HAL provider gem is present in the build, the
 target gem's `ports/<conf.ports>/` sources are dropped from the
 build automatically. The HAL provider's own sources supply the
 implementation instead, avoiding duplicate symbol errors at link
 time. Loading two gems that match the same `hal-<short>-*`
 prefix is a build error.
 The naming convention is the only signal -- no spec attribute,
 no `add_dependency` flag is required. A gem author who wants to
 contribute an additional bundled port upstream sends a PR adding
 `<target-gem>/ports/<name>/`; a gem author who prefers to ship
 out of tree publishes a `hal-<short>-<conf>` gem instead.
 ## C Extension
 mruby can be extended with C. This is possible by using the C API to
@@ -117,8 +117,8 @@ Defined in `include/mruby/class.h`:
 ```c
 union mrb_mt_ptr {
  mrb_func_t func;            /* first member: see MRB_MT_ENTRY note */
  const struct RProc *proc;
  mrb_func_t func;
 };
 typedef struct mrb_mt_entry {
@@ -139,9 +139,12 @@ typedef struct mrb_mt_tbl {
 ```c
 /* ROM table entry: 3rd param is MRB_ARGS_*() optionally OR'd with
-   MRB_MT_PRIVATE.  The macro OR's in MRB_MT_FUNC automatically. */
+   MRB_MT_PRIVATE.  The macro OR's in MRB_MT_FUNC automatically.
   `func` must be the first member of `union mrb_mt_ptr` so that
   positional initialization works on legacy C++ compilers that do
   not accept C99 designated initializers. */
 #define MRB_MT_ENTRY(fn, sym, flags) \
-  { { .func = (fn) }, (sym), (flags) | MRB_MT_FUNC }
+  { { (fn) }, (sym), (flags) | MRB_MT_FUNC }
 /* Extract aspec from combined flags */
 #define MRB_MT_ASPEC(flags) ((mrb_aspec)((flags) & 0xffffff))
@@ -31,17 +31,17 @@ struct RBasic (8 bytes on 64-bit)
 All object structs embed this header via `MRB_OBJECT_HEADER`:
-| Struct | Ruby Type | Extra Fields |
+| Struct       | Ruby Type        | Extra Fields                       |
-| ------ | --------- | ------------ |
+| ------------ | ---------------- | ---------------------------------- |
-| `RObject` | Object instances | `iv` (instance variables) |
+| `RObject`    | Object instances | `iv` (instance variables)          |
-| `RClass` | Class/Module | `iv`, `mt` (method table), `super` |
+| `RClass`     | Class/Module     | `iv`, `mt` (method table), `super` |
-| `RString` | String | embedded or heap buffer, length |
+| `RString`    | String           | embedded or heap buffer, length    |
-| `RArray` | Array | embedded or heap buffer, length |
+| `RArray`     | Array            | embedded or heap buffer, length    |
-| `RHash` | Hash | hash table or k-v array |
+| `RHash`      | Hash             | hash table or k-v array            |
-| `RProc` | Proc/Lambda | `irep` or C function, environment |
+| `RProc`      | Proc/Lambda      | `irep` or C function, environment  |
-| `RData` | C data wrapper | `void *data`, `mrb_data_type` |
+| `RData`      | C data wrapper   | `void *data`, `mrb_data_type`      |
-| `RFiber` | Fiber | `mrb_context` |
+| `RFiber`     | Fiber            | `mrb_context`                      |
-| `RException` | Exception | `iv` |
+| `RException` | Exception        | `iv`                               |
 Immediate values (Integer, Symbol, `true`, `false`, `nil`) are encoded
 directly in `mrb_value` without heap allocation. The encoding depends on
@@ -111,52 +111,52 @@ See [compiler.md](compiler.md) for detailed compiler internals,
 ### Core (`src/`)
-| File | Responsibility |
+| File          | Responsibility                                 |
-| ---- | -------------- |
+| ------------- | ---------------------------------------------- |
-| `vm.c` | Bytecode dispatch loop, method invocation |
+| `vm.c`        | Bytecode dispatch loop, method invocation      |
-| `state.c` | `mrb_state` init/close, irep management |
+| `state.c`     | `mrb_state` init/close, irep management        |
-| `gc.c` | Garbage collector (mark-sweep, incremental) |
+| `gc.c`        | Garbage collector (mark-sweep, incremental)    |
-| `class.c` | Class/module definition, method tables |
+| `class.c`     | Class/module definition, method tables         |
-| `object.c` | Core object operations |
+| `object.c`    | Core object operations                         |
-| `variable.c` | Instance/class/global variables, object shapes |
+| `variable.c`  | Instance/class/global variables, object shapes |
-| `proc.c` | Proc/Lambda/closure handling |
+| `proc.c`      | Proc/Lambda/closure handling                   |
-| `array.c` | Array implementation |
+| `array.c`     | Array implementation                           |
-| `string.c` | String implementation (embedded, shared, heap) |
+| `string.c`    | String implementation (embedded, shared, heap) |
-| `hash.c` | Hash implementation (open addressing) |
+| `hash.c`      | Hash implementation (open addressing)          |
-| `numeric.c` | Integer/Float arithmetic |
+| `numeric.c`   | Integer/Float arithmetic                       |
-| `symbol.c` | Symbol table and interning |
+| `symbol.c`    | Symbol table and interning                     |
-| `range.c` | Range implementation |
+| `range.c`     | Range implementation                           |
-| `error.c` | Exception creation, raise, backtrace |
+| `error.c`     | Exception creation, raise, backtrace           |
-| `kernel.c` | Kernel module methods |
+| `kernel.c`    | Kernel module methods                          |
-| `load.c` | `.mrb` bytecode loading |
+| `load.c`      | `.mrb` bytecode loading                        |
-| `dump.c` | Bytecode serialization (write `.mrb`) |
+| `dump.c`      | Bytecode serialization (write `.mrb`)          |
-| `print.c` | Print/puts/p output |
+| `print.c`     | Print/puts/p output                            |
-| `backtrace.c` | Stack trace generation |
+| `backtrace.c` | Stack trace generation                         |
 ### Compiler (`mrbgems/mruby-compiler/core/`)
-| File | Responsibility |
+| File        | Responsibility                  |
-| ---- | -------------- |
+| ----------- | ------------------------------- |
-| `parse.y` | Yacc grammar → AST |
+| `parse.y`   | Yacc grammar → AST              |
-| `y.tab.c` | Generated parser (from parse.y) |
+| `y.tab.c`   | Generated parser (from parse.y) |
-| `codegen.c` | AST → bytecode (irep) |
+| `codegen.c` | AST → bytecode (irep)           |
-| `node.h` | AST node type definitions |
+| `node.h`    | AST node type definitions       |
 ### Key Headers (`include/mruby/`)
-| Header | Contents |
+| Header       | Contents                              |
-| ------ | -------- |
+| ------------ | ------------------------------------- |
-| `mruby.h` | `mrb_state`, core API declarations |
+| `mruby.h`    | `mrb_state`, core API declarations    |
-| `value.h` | `mrb_value`, type enums, value macros |
+| `value.h`    | `mrb_value`, type enums, value macros |
-| `object.h` | `RBasic`, `RObject`, object header |
+| `object.h`   | `RBasic`, `RObject`, object header    |
-| `class.h` | `RClass`, method table types |
+| `class.h`    | `RClass`, method table types          |
-| `string.h` | `RString`, string macros |
+| `string.h`   | `RString`, string macros              |
-| `array.h` | `RArray`, array macros |
+| `array.h`    | `RArray`, array macros                |
-| `hash.h` | `RHash`, hash API |
+| `hash.h`     | `RHash`, hash API                     |
-| `data.h` | `RData`, C data wrapping |
+| `data.h`     | `RData`, C data wrapping              |
-| `irep.h` | `mrb_irep`, bytecode structures |
+| `irep.h`     | `mrb_irep`, bytecode structures       |
-| `compile.h` | Compiler context, `mrb_load_string` |
+| `compile.h`  | Compiler context, `mrb_load_string`   |
-| `boxing_*.h` | Value boxing implementations |
+| `boxing_*.h` | Value boxing implementations          |
 ## mrbgems System
@@ -77,16 +77,16 @@ No boxing represents `mrb_value` by the C struct with `type` and the value union
 ## Comparison
-| Property               | Word Boxing        | NaN Boxing         | No Boxing            |
+| Property               | Word Boxing       | NaN Boxing       | No Boxing            |
-| ---------------------- | ------------------ | ------------------ | -------------------- |
+| ---------------------- | ----------------- | ---------------- | -------------------- |
-| `mrb_value` size       | 1 word (4/8 byte)  | 8 bytes            | 2 words (8/16 bytes) |
+| `mrb_value` size       | 1 word (4/8 byte) | 8 bytes          | 2 words (8/16 bytes) |
-| Default on             | most platforms     | (manual opt-in)    | `host-debug`         |
+| Default on             | most platforms    | (manual opt-in)  | `host-debug`         |
-| Macro                  | `MRB_WORD_BOXING`  | `MRB_NAN_BOXING`   | `MRB_NO_BOXING`      |
+| Macro                  | `MRB_WORD_BOXING` | `MRB_NAN_BOXING` | `MRB_NO_BOXING`      |
-| Inline integers        | yes (31/63 bit)    | yes (32 bit)       | yes (full width)     |
+| Inline integers        | yes (31/63 bit)   | yes (32 bit)     | yes (full width)     |
-| Inline floats (64-bit) | yes (rotation)     | yes (native)       | yes (struct field)   |
+| Inline floats (64-bit) | yes (rotation)    | yes (native)     | yes (struct field)   |
-| Inline floats (32-bit) | no (heap RFloat)   | yes (native)       | yes (struct field)   |
+| Inline floats (32-bit) | no (heap RFloat)  | yes (native)     | yes (struct field)   |
-| Pointer size limit     | none               | 48 bits            | none                 |
+| Pointer size limit     | none              | 48 bits          | none                 |
-| Debugger friendly      | no                 | no                 | yes                  |
+| Debugger friendly      | no                | no               | yes                  |
 ## ABI Compatibility
@@ -40,18 +40,18 @@ file: `mrbgems/mruby-compiler/core/parse.y`.
 The parser maintains extensive state in `mrb_parser_state`:
- **lstate**: current lexer state (EXPR\_BEG, EXPR\_END, EXPR\_ARG,
+- **lstate**: current lexer state (EXPR_BEG, EXPR_END, EXPR_ARG,
-  EXPR\_DOT, EXPR\_FNAME, etc.). Controls how tokens like `+`/`-`
+  EXPR_DOT, EXPR_FNAME, etc.). Controls how tokens like `+`/`-`
  are interpreted (sign vs operator) and whether newlines are
  significant.
 - **locals**: stack of local variable lists (one per scope), stored
  as cons-lists of symbols.
- **lex\_strterm**: string/heredoc parsing state for handling nested
+- **lex_strterm**: string/heredoc parsing state for handling nested
  interpolation.
- **cond\_stack**, **cmdarg\_stack**: bit stacks tracking
+- **cond_stack**, **cmdarg_stack**: bit stacks tracking
  conditional and command argument contexts.
 - **tree**: root AST node after successful parse.
- **error\_buffer**: accumulated parse errors.
+- **error_buffer**: accumulated parse errors.
 ### AST Nodes
@@ -123,10 +123,10 @@ reuse temporaries within an expression.
 Instructions are emitted via helper functions:
 - `genop_0(opcode)`: no operands
- `genop_1(opcode, a)`: one operand (auto-extends with OP\_EXT1
+- `genop_1(opcode, a)`: one operand (auto-extends with OP_EXT1
  if a > 255)
 - `genop_2(opcode, a, b)`: two operands (auto-extends with
-  OP\_EXT1/2/3 as needed)
+  OP_EXT1/2/3 as needed)
 - `genop_3(opcode, a, b, c)`: three operands
 - `genop_W(opcode, a)`: 24-bit operand
 - `genop_2S(opcode, a, b)`: one 8-bit + one 16-bit operand
@@ -176,14 +176,14 @@ mrb_irep
 Pool entries store constants referenced by instructions:
-| Type | Tag | Description |
+| Type             | Tag | Description                     |
-| ---- | --- | ----------- |
+| ---------------- | --- | ------------------------------- |
-| `IREP_TT_STR` | 0 | Dynamic string (heap allocated) |
+| `IREP_TT_STR`    | 0   | Dynamic string (heap allocated) |
-| `IREP_TT_SSTR` | 2 | Static string (read-only) |
+| `IREP_TT_SSTR`   | 2   | Static string (read-only)       |
-| `IREP_TT_INT32` | 1 | 32-bit integer |
+| `IREP_TT_INT32`  | 1   | 32-bit integer                  |
-| `IREP_TT_INT64` | 3 | 64-bit integer |
+| `IREP_TT_INT64`  | 3   | 64-bit integer                  |
-| `IREP_TT_FLOAT` | 5 | Floating-point number |
+| `IREP_TT_FLOAT`  | 5   | Floating-point number           |
-| `IREP_TT_BIGINT` | 7 | Arbitrary-precision integer |
+| `IREP_TT_BIGINT` | 7   | Arbitrary-precision integer     |
 The code generator deduplicates pool entries: identical strings
 and equal numeric values share the same pool index.
@@ -209,28 +209,28 @@ During exception unwinding, handlers are searched in reverse order
 Standard instructions use 8-bit operands. When a value exceeds
 255, extension prefixes widen operands to 16 bits:
-| Prefix | Effect |
+| Prefix    | Effect                            |
-| ------ | ------ |
+| --------- | --------------------------------- |
-| `OP_EXT1` | First operand (a) becomes 16-bit |
+| `OP_EXT1` | First operand (a) becomes 16-bit  |
 | `OP_EXT2` | Second operand (b) becomes 16-bit |
-| `OP_EXT3` | Both a and b become 16-bit |
+| `OP_EXT3` | Both a and b become 16-bit        |
 Instruction formats:
-| Format | Layout | Size |
+| Format | Layout                        | Size    |
-| ------ | ------ | ---- |
+| ------ | ----------------------------- | ------- |
-| Z | opcode only | 1 byte |
+| Z      | opcode only                   | 1 byte  |
-| B | opcode + a(8) | 2 bytes |
+| B      | opcode + a(8)                 | 2 bytes |
-| BB | opcode + a(8) + b(8) | 3 bytes |
+| BB     | opcode + a(8) + b(8)          | 3 bytes |
-| BBB | opcode + a(8) + b(8) + c(8) | 4 bytes |
+| BBB    | opcode + a(8) + b(8) + c(8)   | 4 bytes |
-| BS | opcode + a(8) + b(16) | 4 bytes |
+| BS     | opcode + a(8) + b(16)         | 4 bytes |
-| BSS | opcode + a(8) + b(16) + c(16) | 6 bytes |
+| BSS    | opcode + a(8) + b(16) + c(16) | 6 bytes |
-| S | opcode + a(16) | 3 bytes |
+| S      | opcode + a(16)                | 3 bytes |
-| W | opcode + a(24) | 4 bytes |
+| W      | opcode + a(24)                | 4 bytes |
 See [opcode.md](opcode.md) for the full instruction table.
-## OP\_ENTER: Argument Specification
+## OP_ENTER: Argument Specification
 `OP_ENTER` encodes a method's argument layout in a 24-bit value
 (W format). The bit fields are defined by the `MRB_ARGS_*` macros:
@@ -258,16 +258,16 @@ string interning for common symbols.
 Generated by `lib/mruby/presym.rb`, the presym table maps symbol
 names to compile-time constants:
-| Macro | Example | Symbol |
+| Macro             | Example               | Symbol        |
-| ----- | ------- | ------ |
+| ----------------- | --------------------- | ------------- |
-| `MRB_SYM(name)` | `MRB_SYM(initialize)` | `:initialize` |
+| `MRB_SYM(name)`   | `MRB_SYM(initialize)` | `:initialize` |
-| `MRB_SYM_B(name)` | `MRB_SYM_B(map)` | `:map!` |
+| `MRB_SYM_B(name)` | `MRB_SYM_B(map)`      | `:map!`       |
-| `MRB_SYM_Q(name)` | `MRB_SYM_Q(nil)` | `:nil?` |
+| `MRB_SYM_Q(name)` | `MRB_SYM_Q(nil)`      | `:nil?`       |
-| `MRB_SYM_E(name)` | `MRB_SYM_E(name)` | `:name=` |
+| `MRB_SYM_E(name)` | `MRB_SYM_E(name)`     | `:name=`      |
-| `MRB_OPSYM(op)` | `MRB_OPSYM(add)` | `:+` |
+| `MRB_OPSYM(op)`   | `MRB_OPSYM(add)`      | `:+`          |
-| `MRB_IVSYM(name)` | `MRB_IVSYM(name)` | `:@name` |
+| `MRB_IVSYM(name)` | `MRB_IVSYM(name)`     | `:@name`      |
-| `MRB_CVSYM(name)` | `MRB_CVSYM(count)` | `:@@count` |
+| `MRB_CVSYM(name)` | `MRB_CVSYM(count)`    | `:@@count`    |
-| `MRB_GVSYM(name)` | `MRB_GVSYM(stdout)` | `:$stdout` |
+| `MRB_GVSYM(name)` | `MRB_GVSYM(stdout)`   | `:$stdout`    |
 ## Binary Format (.mrb)
@@ -299,25 +299,25 @@ mrbc -Boutput source.rb           # C array format
 ## Compilation Limits
-| Limit | Value |
+| Limit                  | Value                         |
-| ----- | ----- |
+| ---------------------- | ----------------------------- |
-| Max nesting depth | 256 (`MRB_CODEGEN_LEVEL_MAX`) |
+| Max nesting depth      | 256 (`MRB_CODEGEN_LEVEL_MAX`) |
-| Max local variables | 255 (uint16 `nlocals`) |
+| Max local variables    | 255 (uint16 `nlocals`)        |
-| Max symbols per irep | 65535 |
+| Max symbols per irep   | 65535                         |
-| Max operand (standard) | 255 (8-bit) |
+| Max operand (standard) | 255 (8-bit)                   |
-| Max operand (extended) | 65535 (16-bit) |
+| Max operand (extended) | 65535 (16-bit)                |
 ## Source Files
-| File | Contents |
+| File                                    | Contents                  |
-| ---- | -------- |
+| --------------------------------------- | ------------------------- |
-| `mrbgems/mruby-compiler/core/parse.y` | Lrama/Bison grammar |
+| `mrbgems/mruby-compiler/core/parse.y`   | Lrama/Bison grammar       |
-| `mrbgems/mruby-compiler/core/y.tab.c` | Generated parser |
+| `mrbgems/mruby-compiler/core/y.tab.c`   | Generated parser          |
-| `mrbgems/mruby-compiler/core/codegen.c` | Code generator |
+| `mrbgems/mruby-compiler/core/codegen.c` | Code generator            |
-| `mrbgems/mruby-compiler/core/node.h` | AST node types |
+| `mrbgems/mruby-compiler/core/node.h`    | AST node types            |
-| `include/mruby/irep.h` | IRep structure definition |
+| `include/mruby/irep.h`                  | IRep structure definition |
-| `include/mruby/compile.h` | Compiler context API |
+| `include/mruby/compile.h`               | Compiler context API      |
-| `include/mruby/ops.h` | Opcode definitions |
+| `include/mruby/ops.h`                   | Opcode definitions        |
-| `src/load.c` | Binary format loader |
+| `src/load.c`                            | Binary format loader      |
-| `src/dump.c` | Binary format writer |
+| `src/dump.c`                            | Binary format writer      |
-| `lib/mruby/presym.rb` | Presym table generator |
+| `lib/mruby/presym.rb`                   | Presym table generator    |
@@ -26,12 +26,12 @@ pauses.
 Every heap-allocated object has a color stored in
 `RBasic::gc_color` (3 bits):
-| Color | Value | Meaning |
+| Color          | Value  | Meaning                              |
-| ----- | ----- | ------- |
+| -------------- | ------ | ------------------------------------ |
-| White (A or B) | 1 or 2 | Unmarked, candidate for collection |
+| White (A or B) | 1 or 2 | Unmarked, candidate for collection   |
-| Gray | 0 | Marked, but children not yet scanned |
+| Gray           | 0      | Marked, but children not yet scanned |
-| Black | 4 | Fully marked and scanned |
+| Black          | 4      | Fully marked and scanned             |
-| Red | 7 | Static/ROM object, never collected |
+| Red            | 7      | Static/ROM object, never collected   |
 The GC uses two white types (A and B) in a flip-flop scheme. At the
 start of each GC cycle, the meaning of "current white" is flipped by
@@ -107,7 +107,7 @@ The GC operates as a three-state machine:
 GC_STATE_ROOT --> GC_STATE_MARK --> GC_STATE_SWEEP --> GC_STATE_ROOT
 ```
-### Root Scan (GC\_STATE\_ROOT)
+### Root Scan (GC_STATE_ROOT)
 Marks objects directly reachable from the VM:
@@ -121,7 +121,7 @@ Marks objects directly reachable from the VM:
 After root scanning, the white color is flipped.
-### Incremental Marking (GC\_STATE\_MARK)
+### Incremental Marking (GC_STATE_MARK)
 Gray objects are popped from the gray stack and their children
 marked. Each step processes a limited number of objects:
@@ -131,13 +131,15 @@ limit = (GC_STEP_SIZE / 100) * step_ratio
 ```
 With default `step_ratio = 200` and `GC_STEP_SIZE = 1024`, the
-limit is 2048 objects per step.
+limit is 2048 objects per step. After each step, `gc_debt` is
 decremented by the actual number of objects processed, so larger
 steps repay more debt.
 When the gray stack is exhausted, the final marking phase re-marks
 the arena and global variables to catch objects created during
 marking, then transitions to sweep.
-### Sweep (GC\_STATE\_SWEEP)
+### Sweep (GC_STATE_SWEEP)
 Iterates through heap pages. For each object:
@@ -273,7 +275,7 @@ From Ruby: `GC.generational_mode = true/false`.
 `mrb_obj_alloc()` is the core allocation function:
 1. If `MRB_GC_STRESS` is defined, run a full GC
-2. If `gc->live >= gc->threshold`, run `mrb_incremental_gc()`
+2. Increment `gc->gc_debt`; if positive, run `mrb_incremental_gc()`
 3. Ensure arena has space (`gc_arena_keep`)
 4. Pop an object from the freelist of `gc->free_heaps`
 5. If no free pages, allocate a new page (`add_heap`)
@@ -299,18 +301,43 @@ The object's type is set to `MRB_TT_FREE` after freeing.
 ## Triggering GC
-### Automatic
+### Debt Model
-GC runs automatically when `gc->live >= gc->threshold` during
+GC uses a **debt-based feedback model** to balance allocation
-object allocation. After each cycle:
+rate against collection work. The key field is `gc->gc_debt`
 (signed integer):
 - **Negative** = credit (GC is ahead, no collection needed)
 - **Zero** = balanced
 - **Positive** = debt (allocation outpacing collection, GC runs)
 Each object allocation increments `gc_debt` by 1. When debt
 goes positive, `mrb_incremental_gc()` runs. Each incremental
 step decrements debt by `GC_STEP_SIZE` (1024), giving credit
 for many future allocations.
 When a GC cycle completes, credit is calculated from
 `interval_ratio`:
 ```text
-threshold = (live_after_mark / 100) * interval_ratio
+credit = (live_after_mark / 100) * interval_ratio - live_after_mark
 minimum: GC_STEP_SIZE (1024)
 gc_debt = -credit
 ```
-With default `interval_ratio = 200`, GC triggers when live objects
+With default `interval_ratio = 200` and 1000 live objects:
-roughly double.
+`credit = (1000/100)*200 - 1000 = 1000`, so approximately 1000
 allocations can occur before the next GC cycle begins.
 ### Malloc Pressure
 When `gc->malloc_threshold` is set (non-zero), the GC also
 tracks bytes allocated through `mrb_realloc_simple()` in
 `gc->malloc_increase`. When `malloc_increase` exceeds
 `malloc_threshold`, the counter resets and an incremental GC
 step runs. This captures memory pressure from large buffers
 (e.g., long strings) that would otherwise be invisible to the
 object-count-based debt model.
 ### Manual
@@ -325,33 +352,136 @@ From Ruby: `GC.start`.
 ### Compile-Time
-| Macro | Default | Description |
+| Macro                          | Default | Description                             |
-| ----- | ------- | ----------- |
+| ------------------------------ | ------- | --------------------------------------- |
-| `MRB_HEAP_PAGE_SIZE` | 1024 | Objects per heap page |
+| `MRB_HEAP_PAGE_SIZE`           | 1024    | Objects per heap page                   |
-| `MRB_GRAY_STACK_SIZE` | 1024 | Gray stack capacity |
+| `MRB_GRAY_STACK_SIZE`          | 1024    | Gray stack capacity                     |
-| `MRB_GC_ARENA_SIZE` | 100 | Arena size (fixed mode) or initial size |
+| `MRB_GC_ARENA_SIZE`            | 100     | Arena size (fixed mode) or initial size |
-| `MRB_GC_FIXED_ARENA` | off | Use fixed-size arena |
+| `MRB_GC_FIXED_ARENA`           | off     | Use fixed-size arena                    |
-| `MRB_GC_TURN_OFF_GENERATIONAL` | off | Disable generational mode |
+| `MRB_GC_TURN_OFF_GENERATIONAL` | off     | Disable generational mode               |
-| `MRB_GC_STRESS` | off | Full GC on every allocation (debug) |
+| `MRB_GC_STRESS`                | off     | Full GC on every allocation (debug)     |
-| `MRB_USE_MALLOC_TRIM` | off | Call `malloc_trim()` after full GC |
+| `MRB_GC_STATS`                 | off     | Enable GC statistics counters           |
 | `MRB_USE_MALLOC_TRIM`          | off     | Call `malloc_trim()` after full GC      |
 ### Runtime
 From Ruby code:
 ```ruby
-GC.interval_ratio = 200   # threshold = live * ratio / 100
+GC.interval_ratio = 200     # controls debt credit after GC cycle
-GC.step_ratio = 200       # objects per incremental step
+GC.step_ratio = 200         # objects per incremental step
 GC.step_limit = 0           # 0=unlimited, >0=absolute step cap
 GC.malloc_threshold = 0     # 0=disabled, >0=bytes to trigger GC
 GC.generational_mode = true
-GC.start                   # force full GC
+GC.start                     # force full GC
-GC.enable                  # re-enable GC
+GC.enable                    # re-enable GC
-GC.disable                 # disable GC
+GC.disable                   # disable GC
 ```
 ### GC Statistics
 `GC.stat` returns a Hash with GC state and statistics:
 ```ruby
 GC.stat
 # => {
 #   :live => 5432,              # live object count
 #   :debt => -1024,             # GC debt (negative=credit, positive=behind)
 #   :state => 0,                # 0=root, 1=marking, 2=sweeping
 #   :generational => true,      # generational mode enabled
 #   :full => false,             # major GC in progress
 #   :step_limit => 0,           # current step limit setting
 #   :malloc_increase => 8192,   # malloc bytes since last cycle
 #   :malloc_threshold => 0,     # current malloc threshold setting
 # }
 ```
 With `MRB_GC_STATS` enabled, additional keys are available:
 ```ruby
 #   :total => 15,               # total GC invocations
 #   :minor => 12,               # minor GC count
 #   :major => 3,                # major GC count
 ```
 ### Tuning Guide
 **`interval_ratio`** (default 200): Controls how many allocations
 occur between GC cycles. Higher values reduce GC frequency but
 increase peak memory. The debt credit after each cycle is
 `(live_after_mark / 100) * interval_ratio - live_after_mark`.
 **`step_ratio`** (default 200): Controls how much work each
 incremental step performs. Higher values make each step larger,
 reducing total GC overhead but increasing individual pause times.
 **`step_limit`** (default 0, unlimited): Caps the maximum work
 per incremental step regardless of `step_ratio`. Useful for
 real-time applications that need bounded pause times. The
 effective step size is `min(step_ratio calculation, step_limit)`.
 **`malloc_threshold`** (default 0, disabled): Triggers GC when
 cumulative `malloc`/`realloc` bytes exceed this threshold. Useful
 when applications allocate large buffers (strings, data objects)
 that create memory pressure without proportional object count
 increase.
 ### Practical Tuning Examples
 **Allocation-heavy workloads** (many short-lived Procs, closures,
 blocks): GC sweep dominates because of high object churn. Increase
 `interval_ratio` to reduce GC frequency:
 ```ruby
 GC.interval_ratio = 400  # ~12% faster than default (200)
 ```
 Higher values (400-600) reduce sweep overhead at the cost of more
 dead objects accumulating before collection. Values above 600 show
 diminishing returns. Peak memory usage increases temporarily, but
 live object count after GC remains the same.
 **CPU-intensive workloads** (numeric computation, recursive methods
 with no object allocation): GC parameters have negligible impact
 because GC rarely runs. No tuning needed.
 **Real-time or latency-sensitive** applications: Use `step_limit`
 to bound pause times:
 ```ruby
 GC.step_limit = 256  # cap incremental step to 256 objects
 ```
 This makes GC pauses more predictable but increases total GC
 overhead (more steps needed per cycle).
 **Large buffer workloads** (reading files, building long strings):
 Set `malloc_threshold` to trigger GC when buffer allocations
 accumulate, even if object count is low:
 ```ruby
 GC.malloc_threshold = 1024 * 1024  # trigger GC per ~1MB allocated
 ```
 ### Diagnosing GC Overhead
 Use `GC.stat` to monitor GC behavior at runtime:
 ```ruby
 s = GC.stat
 puts "live objects: #{s[:live]}"
 puts "GC debt: #{s[:debt]}"     # positive = GC is behind
 puts "GC state: #{s[:state]}"   # 0=idle, 1=marking, 2=sweeping
 ```
 If `debt` is frequently positive during performance-critical
 sections, increase `interval_ratio`. If memory usage is too high,
 decrease it.
 ## Source Files
-| File | Contents |
+| File                 | Contents                          |
-| ---- | -------- |
+| -------------------- | --------------------------------- |
-| `src/gc.c` | GC implementation (~1400 lines) |
+| `src/gc.c`           | GC implementation                 |
 | `include/mruby/gc.h` | `mrb_gc` structure, public GC API |
-| `include/mruby.h` | Arena save/restore macros |
+| `include/mruby.h`    | Arena save/restore macros         |
@@ -97,12 +97,12 @@ return n + 1 (skip self)
 ### Call Context Info (cci)
-| Value | Name | Meaning |
+| Value | Name            | Meaning                               |
-| ----- | ---- | ------- |
+| ----- | --------------- | ------------------------------------- |
-| 0 | `CINFO_NONE` | Normal VM-to-VM call |
+| 0     | `CINFO_NONE`    | Normal VM-to-VM call                  |
-| 1 | `CINFO_DIRECT` | Explicit VM call (block, lambda.call) |
+| 1     | `CINFO_DIRECT`  | Explicit VM call (block, lambda.call) |
-| 2 | `CINFO_SKIP` | Skip frame in stack traces |
+| 2     | `CINFO_SKIP`    | Skip frame in stack traces            |
-| 3 | `CINFO_RESUMED` | Fiber resumed (stop execution) |
+| 3     | `CINFO_RESUMED` | Fiber resumed (stop execution)        |
 ## Dispatch Loop
@@ -241,13 +241,13 @@ correctness.
 ### Proc Types
-| Flag | Meaning |
+| Flag                | Meaning                        |
-| ---- | ------- |
+| ------------------- | ------------------------------ |
-| `MRB_PROC_CFUNC_FL` | C function (not irep-based) |
+| `MRB_PROC_CFUNC_FL` | C function (not irep-based)    |
-| `MRB_PROC_STRICT` | Lambda (strict argument check) |
+| `MRB_PROC_STRICT`   | Lambda (strict argument check) |
-| `MRB_PROC_ORPHAN` | No environment attachment |
+| `MRB_PROC_ORPHAN`   | No environment attachment      |
-| `MRB_PROC_ENVSET` | Has captured environment |
+| `MRB_PROC_ENVSET`   | Has captured environment       |
-| `MRB_PROC_SCOPE` | Defines a new variable scope |
+| `MRB_PROC_SCOPE`    | Defines a new variable scope   |
 ## Fiber Switching
@@ -317,9 +317,9 @@ ensuring the incremental GC correctly tracks live references.
 ## Source Files
-| File | Contents |
+| File                    | Contents                                       |
-| ---- | -------- |
+| ----------------------- | ---------------------------------------------- |
-| `src/vm.c` | Dispatch loop, method invocation (~1900 lines) |
+| `src/vm.c`              | Dispatch loop, method invocation (~1900 lines) |
-| `include/mruby.h` | `mrb_state`, `mrb_callinfo`, `mrb_context` |
+| `include/mruby.h`       | `mrb_state`, `mrb_callinfo`, `mrb_context`     |
-| `include/mruby/proc.h` | `RProc`, `REnv` structures |
+| `include/mruby/proc.h`  | `RProc`, `REnv` structures                     |
-| `include/mruby/throw.h` | `MRB_TRY`/`MRB_CATCH` macros |
+| `include/mruby/throw.h` | `MRB_TRY`/`MRB_CATCH` macros                   |
@@ -15,6 +15,23 @@ This document is collecting these limitations.
 This document does not contain a complete list of limitations.
 Please help to improve it by submitting your findings.
 ## Features provided by mrbgems
 Many Ruby features that CRuby builds into its core are provided by
 mrbgems in mruby. Which features are actually available depends on
 which mrbgems are linked into the build. The `default.gembox` and
 `stdlib.gembox` cover the common cases, but a minimal build can omit
 familiar features such as `Kernel#binding` (provided by
 `mruby-binding`), `Kernel#catch`/`throw` (by `mruby-catch`),
 `Enumerable` extensions, `Comparable`, IO, regular expressions, and
 many more.
 This is by design rather than a limitation per se. When porting Ruby
 code to mruby, a `NoMethodError` or `NameError` often means "the gem
 providing this feature is not linked in" rather than "mruby does not
 support it." Adding the relevant gem to the build configuration is
 usually enough.
 ## `Kernel.raise` in rescue clause
 `Kernel.raise` without arguments does not raise the current exception within
@@ -133,12 +150,6 @@ The re-defined `+` operator does not accept any arguments.
 `'ab'`
 Behavior of the operator wasn't changed.
 ## `Kernel#binding` is not supported without mruby-binding gem
 `Kernel#binding` method requires the `mruby-binding` gem (included
 in the `metaprog` gembox). Without this gem, `binding` is not
 available.
 ## `nil?` redefinition in conditional expressions
 Redefinition of `nil?` is ignored in conditional expressions.
@@ -274,11 +285,11 @@ enabled with the `MRB_UTF8_STRING` compile flag.
 Integer size depends on the value boxing configuration:
-| Configuration | Integer range |
+| Configuration                 | Integer range    |
-| ------------- | ------------- |
+| ----------------------------- | ---------------- |
 | Word boxing, 64-bit (default) | roughly +/- 2^62 |
 | Word boxing, 32-bit (default) | roughly +/- 2^30 |
-| NaN boxing (64-bit only) | -2^31 to 2^31-1 |
+| NaN boxing (64-bit only)      | -2^31 to 2^31-1  |
 Code relying on 64-bit integer precision may behave differently
 across configurations. The `mruby-bigint` gem provides
@@ -290,3 +301,151 @@ arbitrary-precision integers when included.
 (included in the `stdlib` gembox). Even with the gem,
 `ObjectSpace.each_object` has limited functionality compared
 to CRuby.
 ## No Implicit Type Conversion (`to_int`, `to_str`, `to_ary`, ...)
 mruby does not perform implicit type conversion through methods
 like `to_int`, `to_str`, `to_ary`, or `to_hash`. CRuby uses these
 to let user-defined classes duck-type as built-in types — for
 example `Array#[]` calls `to_int` on its argument, `String#+` calls
 `to_str`, and multiple assignment calls `to_ary` on its right-hand
 side. mruby's built-in operations require the actual built-in type
 and do not consult these conversion methods.
 ```ruby
 class MyInt;  def to_int; 42; end;     end
 class MyStr;  def to_str; "x"; end;    end
 class MyAry;  def to_ary; [1,2,3]; end; end
 ```
 #### CRuby
 ```
 [1,2,3][MyInt.new]   # => nil   (to_int called -> ary[42])
 "a" + MyStr.new      # => "ax"  (to_str called)
 a, b, c = MyAry.new  # => a=1, b=2, c=3   (to_ary called)
 ```
 #### mruby
 ```
 [1,2,3][MyInt.new]   # TypeError
 "a" + MyStr.new      # TypeError
 a, b, c = MyAry.new  # a=<MyAry obj>, b=nil, c=nil   (treated as single value)
 ```
 Identity versions of `to_int`, `to_str`, `to_sym`, and `to_hash`
 remain defined on the corresponding built-in types so that
 `respond_to?(:to_str)`-style checks work for built-in instances.
 `Float#to_int` and `Array#to_ary` are intentionally not defined.
 Explicit conversion methods (`to_i`, `to_s`, `to_a`) work as in
 CRuby and are called by features such as string interpolation and
 the splat operator (`*obj`).
 This is a deliberate trade-off: implicit conversion forces every
 coercion site to go through method dispatch and can silently mask
 type-mismatch bugs.
 ## Nested `def` in Singleton-Method Context
 `def` written inside a singleton method (`def self.foo`) is placed
 on a different class in mruby than in CRuby. CRuby registers the
 inner method as an instance method of the lexical enclosing class.
 mruby registers it as a method of the enclosing receiver's
 singleton class, which makes it visible as a class method of the
 enclosing class.
 ```ruby
 class SomeClass
  def self.class_method
    def nested; 'nested!'; end
  end
 end
 SomeClass.class_method
 ```
 #### CRuby
 ```
 SomeClass.nested        # NoMethodError
 SomeClass.new.nested    # => "nested!"   (instance method)
 ```
 #### mruby
 ```
 SomeClass.nested        # => "nested!"   (class method)
 SomeClass.new.nested    # NoMethodError
 ```
 Writing nested `def` like this is unusual; this difference rarely
 surfaces in practical code.
 ## `Proc#dup` / `Proc#clone` is Always Orphan
 A `dup` or `clone` of a block given to a method is always treated as
 an orphan block in mruby — calling it raises `LocalJumpError` if the
 block contains `break` or `return`. CRuby is finer-grained: the copy
 inherits the orphan status of its original, so the copy only becomes
 orphan once the original yielding method returns.
 ```ruby
 def m(&b)
  b.dup
 end
 x = m { break 1 }
 x.call
 ```
 #### CRuby
 ```
 LocalJumpError  # raised only after m returns; if called inside m,
                # the dup is still a live block
 ```
 #### mruby
 ```
 LocalJumpError  # always raised — the dup is orphan from the moment
                # it is created
 ```
 mruby's stricter rule keeps `RProc` from needing a back-pointer to
 the original block (which would also enlarge the GC mark set).
 ## `Class#initialize` Can Be Re-Invoked
 CRuby raises `TypeError: already initialized class` when `initialize`
 is invoked on a class that has already been set up. mruby's
 `Class#initialize` has no such guard — invoking it on an existing
 class through `__send__`, `send`, or `UnboundMethod#bind_call`
 silently succeeds. The superclass argument is ignored in this case,
 so the call cannot rewrite the class hierarchy; only the block (if
 any) is evaluated with the class as receiver.
 ```ruby
 Klass = Class.new
 Klass.__send__(:initialize) {}
 ```
 #### CRuby
 ```
 TypeError: already initialized class
 ```
 #### mruby
 ```
 The block is evaluated in the context of Klass; no error is raised.
 The superclass is not changed even when one is passed as an argument.
 ```
 `Module#initialize` is re-callable in both implementations, so this
 divergence is `Class`-specific. Adding the CRuby check would require
 an additional flag bit on every `RClass`; mruby leaves the bit
 unspent because no destructive side effects are possible through
 this path.
@@ -0,0 +1,367 @@
 # User visible changes in `mruby4.0` from `mruby3.4`
 "**_NOTE_**:" are changes to be aware of.
 # The language
 ## Pattern Matching
 mruby now supports pattern matching (case/in) syntax:
 - Basic pattern matching with `case`/`in` syntax ([dadfac6](https://github.com/mruby/mruby/commit/dadfac6))
 - Array pattern matching ([ec67fd9](https://github.com/mruby/mruby/commit/ec67fd9))
 - Hash pattern matching ([2147263](https://github.com/mruby/mruby/commit/2147263))
 - Find pattern matching (`[*pre, target, *post]`) ([6c4d98b](https://github.com/mruby/mruby/commit/6c4d98b))
 - Pin operator (`^variable`) ([1de6340](https://github.com/mruby/mruby/commit/1de6340))
 - Guard clauses (`if`/`unless` conditions) ([07ac110](https://github.com/mruby/mruby/commit/07ac110))
 - One-line pattern matching (`expr in pattern`) ([e76ce24](https://github.com/mruby/mruby/commit/e76ce24))
 - Brace-less hash pattern support ([e8096bf](https://github.com/mruby/mruby/commit/e8096bf))
 ## Other Language Changes
 - `&nil` in formal parameters to explicitly opt out of block arguments ([b07518e](https://github.com/mruby/mruby/commit/b07518e))
 - Trailing comma in method definition parameters: `def foo(a, b,)` ([f78334b](https://github.com/mruby/mruby/commit/f78334b))
 - Array/Hash/String subclasses can now override `[]` and `[]=` methods ([#6675](https://github.com/mruby/mruby/pull/6675))
 - `OP_SETIDX` optimization for Array and Hash ([ddd8fe1](https://github.com/mruby/mruby/commit/ddd8fe1))
 - `case`/`in` without `else` now raises `NoMatchingPatternError` ([d8de35b](https://github.com/mruby/mruby/commit/d8de35b))
 - Allow compound statement in parenthesized argument context ([919cbd8](https://github.com/mruby/mruby/commit/919cbd8))
 # Changes in C API
 - **_NOTE_**: `mrb_alloca()` renamed to `mrb_temp_alloc()` ([7fe5c2e](https://github.com/mruby/mruby/commit/7fe5c2e))
 - **_NOTE_**: `mruby/ext/io.h` renamed to `mruby/io.h` ([2813f79](https://github.com/mruby/mruby/commit/2813f79))
 - `mrb_gc_add_region()` for contiguous heap region support ([072855a](https://github.com/mruby/mruby/commit/072855a))
 - `mrb_class_outer()` to get the outer class/module ([3a1b771](https://github.com/mruby/mruby/commit/3a1b771))
 - `MRB_ENSURE()` macro for exception-safe cleanup ([3ac682b](https://github.com/mruby/mruby/commit/3ac682b))
 - `mrb_time_get_tm()` for accessing struct tm ([daaaafe](https://github.com/mruby/mruby/commit/daaaafe))
 - `MRB_OPEN_FAILURE()` macro for checking mrb_open result ([40b0cb9](https://github.com/mruby/mruby/commit/40b0cb9))
 - `mrb_print_error()` now handles NULL gracefully ([8e50a45](https://github.com/mruby/mruby/commit/8e50a45))
 - `mrb_open()` returns mrb_state with exc set on init failure ([05ffe0c](https://github.com/mruby/mruby/commit/05ffe0c))
 - `mrb_utf8_to_buf()` for UTF-8 encoding consolidation ([7e28e68](https://github.com/mruby/mruby/commit/7e28e68))
 - `kh_is_end()` macro for safe khash iteration ([893cc75](https://github.com/mruby/mruby/commit/893cc75))
 - `mrb_bigint_p()` always defined regardless of bigint gem presence ([6c4a8c0](https://github.com/mruby/mruby/commit/6c4a8c0))
 - `RInteger` and `RFloat` added to `RVALUE` union ([13dbca0](https://github.com/mruby/mruby/commit/13dbca0))
 # ROM Method Tables
 All built-in classes and most extension gems now use read-only method
 tables stored in `.rodata` instead of heap-allocated hash tables. Method
 definitions no longer consume heap memory, significantly reducing memory
 footprint for embedded use.
 Core classes converted: BasicObject, Object, Module, Class, Kernel,
 String, Array, Hash, Numeric, Integer, Float, NilClass, TrueClass,
 FalseClass, Range, Symbol, Exception, Proc.
 Extension gems converted: mruby-string-ext, mruby-array-ext, mruby-set,
 mruby-struct, mruby-class-ext, mruby-numeric-ext, mruby-random,
 mruby-kernel-ext, mruby-complex, mruby-rational, mruby-io, mruby-socket,
 mruby-method, mruby-metaprog, mruby-time, mruby-hash-ext, mruby-proc-ext,
 mruby-symbol-ext, mruby-range-ext, mruby-object-ext.
 # GC and Memory
 - **_NOTE_**: `MRB_NO_PRESYM` removed; presym is now always enabled ([81689045](https://github.com/mruby/mruby/commit/81689045))
 - Replace `gcnext` gray linked list with fixed-size gray stack, reducing per-object overhead ([31fea170](https://github.com/mruby/mruby/commit/31fea170))
 - `mrb_gc_add_region()` for providing contiguous memory buffers as GC heap pages ([072855a](https://github.com/mruby/mruby/commit/072855a))
 - Chunk-based pool for symbol string allocation ([e05bd8f](https://github.com/mruby/mruby/commit/e05bd8f))
 - Reduce `IV_INITIAL_SIZE` from 4 to 2 ([6bd1f51](https://github.com/mruby/mruby/commit/6bd1f51))
 - Lossless float encoding using rotation in word boxing ([b6148c8](https://github.com/mruby/mruby/commit/b6148c8))
 - Lossless rotation encoding for 32-bit float32 word boxing ([14a5cfb](https://github.com/mruby/mruby/commit/14a5cfb))
 - Consolidated irep allocation for .mrb loading ([74fb045](https://github.com/mruby/mruby/commit/74fb045))
 - Object shapes (hidden classes) for `MRB_TT_OBJECT` IV storage, sharing key layouts across objects with the same instance variable assignment order ([8d10056](https://github.com/mruby/mruby/commit/8d10056))
 # Build & Configuration
 - **_NOTE_**: `MRB_WORDBOX_NO_FLOAT_TRUNCATE` renamed to `MRB_WORDBOX_NO_INLINE_FLOAT` (old name still works) ([59e1fe2](https://github.com/mruby/mruby/commit/59e1fe2))
 - **_NOTE_**: `MRB_INT64` on 32-bit now requires `MRB_NO_BOXING` (other boxing modes cannot guarantee alignment for heap-allocated 64-bit integers) ([eaaa66b](https://github.com/mruby/mruby/commit/eaaa66b))
 - Amalgamation support via `rake amalgam` task ([d995ca2](https://github.com/mruby/mruby/commit/d995ca2))
 - New Platform: Cosmopolitan Libc ([#6681](https://github.com/mruby/mruby/pull/6681))
 - Emscripten: use native WASM exception handling ([ca364e3](https://github.com/mruby/mruby/commit/ca364e3))
 - HAL (Hardware Abstraction Layer) for platform abstraction in mruby-io, mruby-socket, mruby-dir, mruby-task ([74ca22f](https://github.com/mruby/mruby/commit/74ca22f))
 - `MRUBY_MIRB_READLINE` environment variable to control readline library selection ([0aafb83](https://github.com/mruby/mruby/commit/0aafb83))
 - MSYS2 drive letter support in build script ([77f6ffe](https://github.com/mruby/mruby/commit/77f6ffe))
 - Inter-gem headers separated from external API headers ([#6671](https://github.com/mruby/mruby/pull/6671))
 # Changes in mrbgems
 ## New Gems
 - **mruby-task**: Cooperative multitasking with preemptive scheduling ([ae0d7a0](https://github.com/mruby/mruby/commit/ae0d7a0))
 - **mruby-benchmark**: Benchmarking gem ([2f40f3d](https://github.com/mruby/mruby/commit/2f40f3d))
 - **mruby-strftime**: Time#strftime implementation ([b31e22f](https://github.com/mruby/mruby/commit/b31e22f))
 ## mruby-bin-mirb Improvements
 - Custom multi-line editor replacing readline ([527018c](https://github.com/mruby/mruby/commit/527018c))
 - Syntax highlighting for keywords, strings, result values, hash key symbols ([624272b](https://github.com/mruby/mruby/commit/624272b), [1713d4a](https://github.com/mruby/mruby/commit/1713d4a))
 - Automatic light/dark theme detection via OSC 11 ([db4c8d9](https://github.com/mruby/mruby/commit/db4c8d9))
 - Tab completion support ([2f15282](https://github.com/mruby/mruby/commit/2f15282))
 - Colored output for prompts and errors ([b36e0b4](https://github.com/mruby/mruby/commit/b36e0b4))
 - Auto-indentation and auto-dedent ([d52f318](https://github.com/mruby/mruby/commit/d52f318), [e901b6d](https://github.com/mruby/mruby/commit/e901b6d))
 - Command history with Up/Down navigation ([5f85c1b](https://github.com/mruby/mruby/commit/5f85c1b))
 - Line numbers in multi-line prompts ([5a3f0e2](https://github.com/mruby/mruby/commit/5a3f0e2))
 - UTF-8 multibyte character support ([4a97da3](https://github.com/mruby/mruby/commit/4a97da3))
 ## mruby-bigint Improvements
 - Toom-3 multiplication for large numbers ([99620804](https://github.com/mruby/mruby/commit/99620804))
 - Karatsuba multiplication for medium-sized numbers ([85e81072](https://github.com/mruby/mruby/commit/85e81072))
 - Balance multiplication for asymmetric operands ([0220ec2b](https://github.com/mruby/mruby/commit/0220ec2b))
 - Divide-and-conquer optimization for `to_s` ([990ff90f](https://github.com/mruby/mruby/commit/990ff90f))
 - Consolidated mpn layer for low-level limb operations ([9ef3362f](https://github.com/mruby/mruby/commit/9ef3362f))
 - Always use 32-bit limbs by default ([c747c77f](https://github.com/mruby/mruby/commit/c747c77f))
 ## Other Gem Changes
 - **_NOTE_**: `Hash#deconstruct_keys` removed for CRuby compatibility ([34b9412](https://github.com/mruby/mruby/commit/34b9412))
 - **mruby-enum-lazy**: Fix `Lazy#flat_map` to handle non-enumerable block return values ([#6765](https://github.com/mruby/mruby/pull/6765))
 - **mruby-array-ext**: Add `Array#find` and `Array#rfind` methods
 - **mruby-io**: Add `IO#putc` and `Kernel#putc` ([baff6e6](https://github.com/mruby/mruby/commit/baff6e6))
 - **mruby-random**: Replace xoshiro with PCG for better memory efficiency ([f1bab01](https://github.com/mruby/mruby/commit/f1bab01))
 - **mruby-compiler**: Variable-sized AST nodes for reduced memory usage
 - **mruby-compiler**: `no_return_value` context flag for script optimization ([613b03a](https://github.com/mruby/mruby/commit/613b03a))
 - `initialize_copy` and `respond_to_missing?` defined as private ([#6708](https://github.com/mruby/mruby/pull/6708))
 - Struct keyword argument initialization ([#6574](https://github.com/mruby/mruby/pull/6574))
 # Compiler Improvements
 - Variable-sized AST nodes for reduced memory consumption ([821b989](https://github.com/mruby/mruby/commit/821b989))
 - Pattern matching bytecode optimizations ([21d4135](https://github.com/mruby/mruby/commit/21d4135))
 - Optimized masgn to generate literals directly into target registers ([fb5d966](https://github.com/mruby/mruby/commit/fb5d966))
 - Optimized splat of literal arrays in args/literals ([1cb8d73](https://github.com/mruby/mruby/commit/1cb8d73))
 - Early termination after too many parse errors ([510ebd7](https://github.com/mruby/mruby/commit/510ebd7))
 - Chunk array literals at 64 elements to reduce register pressure ([f98d641](https://github.com/mruby/mruby/commit/f98d641))
 - Chunk `%w()` and `%i()` literals to reduce register pressure ([62cf0dc](https://github.com/mruby/mruby/commit/62cf0dc))
 # VM Optimizations
 New super-instructions that fuse common opcode sequences to reduce bytecode size and improve performance:
 - `OP_SEND0`/`OP_SSEND0`: Zero-argument method call, avoiding argument count setup ([9123ef4](https://github.com/mruby/mruby/commit/9123ef4))
 - `OP_TDEF`/`OP_SDEF`: Fused method definition combining TCLASS/SCLASS+METHOD+DEF into single instruction, saving 4 bytes per method ([8d4f47e](https://github.com/mruby/mruby/commit/8d4f47e))
 - `OP_GETIDX0`: Fast path for `array[0]` and `Array#first` access ([680f7ec](https://github.com/mruby/mruby/commit/680f7ec))
 - `OP_ADDILV`/`OP_SUBILV`: Local variable increment/decrement fusion for `i += n` patterns ([43f64b9](https://github.com/mruby/mruby/commit/43f64b9))
 - `OP_RETSELF`: Single-byte instruction for `return self` pattern ([a71db8c](https://github.com/mruby/mruby/commit/a71db8c))
 - `OP_RETNIL`: Single-byte instruction for `return nil` pattern ([64e30bf](https://github.com/mruby/mruby/commit/64e30bf))
 - `OP_RETTRUE`/`OP_RETFALSE`: Single-byte instructions for `return true`/`return false` patterns ([0b15727](https://github.com/mruby/mruby/commit/0b15727))
 - `OP_MATCHERR`: Pattern matching error with conditional execution ([944168a](https://github.com/mruby/mruby/commit/944168a))
 - `OP_BLKCALL`: Direct block call for `yield`, bypassing method dispatch (13-17% faster) ([3aa2872](https://github.com/mruby/mruby/commit/3aa2872))
 Other optimizations:
 - 1.5x stack growth instead of linear growth for reduced reallocations ([f7988c93](https://github.com/mruby/mruby/commit/f7988c93))
 - Skip keyword argument hash duplication ([5970e350](https://github.com/mruby/mruby/commit/5970e350))
 # Fixed GitHub Issues
 - [#5531](https://github.com/mruby/mruby/issues/5531) Hash recursion detection
 - [#6506](https://github.com/mruby/mruby/issues/6506) Constant lookup in singleton class
 - [#6507](https://github.com/mruby/mruby/issues/6507) tally multi-values
 - [#6508](https://github.com/mruby/mruby/issues/6508) Enumerable#sum index
 - [#6509](https://github.com/mruby/mruby/issues/6509) scope_new nregs initialization
 - [#6515](https://github.com/mruby/mruby/issues/6515) y.tab.c in repository
 - [#6516](https://github.com/mruby/mruby/issues/6516) Private backquote
 - [#6554](https://github.com/mruby/mruby/issues/6554) Socket private #initialize
 - [#6570](https://github.com/mruby/mruby/issues/6570) instance_eval crash
 - [#6613](https://github.com/mruby/mruby/issues/6613) const_added hook during bootstrapping
 - [#6635](https://github.com/mruby/mruby/issues/6635), [#6636](https://github.com/mruby/mruby/issues/6636) Colon3 constant lookup
 - [#6637](https://github.com/mruby/mruby/issues/6637) arm64 mingw64 builtin setjmp/longjmp
 - [#6642](https://github.com/mruby/mruby/issues/6642) Task segfault when sleep called from C
 - [#6645](https://github.com/mruby/mruby/issues/6645) Set memory leak from double initialization
 - [#6646](https://github.com/mruby/mruby/issues/6646) IO#gets negative length
 - [#6647](https://github.com/mruby/mruby/issues/6647) IO#ungetc buffer overflow
 - [#6648](https://github.com/mruby/mruby/issues/6648) sprintf buffer overread
 - [#6649](https://github.com/mruby/mruby/issues/6649) Array#sort! use-after-realloc
 - [#6650](https://github.com/mruby/mruby/issues/6650) Array#fill validation
 - [#6652](https://github.com/mruby/mruby/issues/6652) Array comparison use-after-realloc
 - [#6657](https://github.com/mruby/mruby/issues/6657) Exception handling for ||= on class variables
 - [#6659](https://github.com/mruby/mruby/issues/6659) Super with keyword arguments
 - [#6660](https://github.com/mruby/mruby/issues/6660) Regression on struct/array/hash == override with super
 - [#6662](https://github.com/mruby/mruby/issues/6662) Array set operations use-after-free
 - [#6664](https://github.com/mruby/mruby/issues/6664) Set#flatten memory leak
 - [#6666](https://github.com/mruby/mruby/issues/6666) Regexp literal with encoding
 - [#6668](https://github.com/mruby/mruby/issues/6668) Method#== for aliased methods and comparison bug
 - [#6671](https://github.com/mruby/mruby/issues/6671) Separate inter-gem headers from external API headers
 - [#6674](https://github.com/mruby/mruby/issues/6674) Document pattern matching limitations
 - [#6675](https://github.com/mruby/mruby/issues/6675) Allow Hash#[] to be aliased again
 - [#6687](https://github.com/mruby/mruby/issues/6687) Expand MRB_SYM/MRB_GVSYM support for symbols with special characters
 - [#6698](https://github.com/mruby/mruby/issues/6698) Bigint tests fail on architectures other than x86_64 and i386
 - [#6701](https://github.com/mruby/mruby/issues/6701) Heap-use-after-free in mrb_vm_exec involving mruby-rational / mruby-bigint
 - [#6702](https://github.com/mruby/mruby/issues/6702) mruby-bigint doesn't compile in C++ project
 - [#6704](https://github.com/mruby/mruby/issues/6704) Heap-buffer-overflow in mrb_vm_exec via malformed source code
 - [#6705](https://github.com/mruby/mruby/issues/6705) Can't get outer class of an object in C
 - [#6713](https://github.com/mruby/mruby/issues/6713) mruby-polarssl not work
 - [#6720](https://github.com/mruby/mruby/issues/6720) Random float range: different behavior from CRuby
 - [#6722](https://github.com/mruby/mruby/issues/6722) RBreak size overflow on 32-bit platforms with MRB_NO_BOXING
 - [#6740](https://github.com/mruby/mruby/issues/6740) `%w()`/`%i()` register pressure with large literals
 - [#6741](https://github.com/mruby/mruby/issues/6741) `case`/`in` without `else` should raise `NoMatchingPatternError`
 - [#6760](https://github.com/mruby/mruby/issues/6760) `mrb_gc_unregister()` not removing all matching entries
 # Merged Pull Requests
 - [#6418](https://github.com/mruby/mruby/pull/6418) Add `ls-lint` with GitHub Actions
 - [#6492](https://github.com/mruby/mruby/pull/6492) fix a typo, update specs
 - [#6493](https://github.com/mruby/mruby/pull/6493) Fix TYPO in memory.md
 - [#6495](https://github.com/mruby/mruby/pull/6495) Remove `MRB_ENDIAN_LOHI()` that is no longer in use
 - [#6497](https://github.com/mruby/mruby/pull/6497) gha: update `build.yml` try `windows-2025` image
 - [#6498](https://github.com/mruby/mruby/pull/6498) Clean up and standardize the pre-commit config
 - [#6501](https://github.com/mruby/mruby/pull/6501) Update pre-commit Node.js version to `v22.14.0 LTS`
 - [#6502](https://github.com/mruby/mruby/pull/6502) pre-commit: update prettier to the latest version
 - [#6503](https://github.com/mruby/mruby/pull/6503) misc: fix typos
 - [#6505](https://github.com/mruby/mruby/pull/6505) mrbgems: fix spelling
 - [#6510](https://github.com/mruby/mruby/pull/6510) Fixed class method visibility via `module_function`
 - [#6511](https://github.com/mruby/mruby/pull/6511) Exclude the external project "lrama" from pre-commit
 - [#6513](https://github.com/mruby/mruby/pull/6513) mruby 3.4.0 released
 - [#6517](https://github.com/mruby/mruby/pull/6517) core/codegen.c: remove unneeded duplicate semicolon
 - [#6518](https://github.com/mruby/mruby/pull/6518) Change mrbc_args.flags bit width from 2 to 3
 - [#6519](https://github.com/mruby/mruby/pull/6519) Add `tools/lrama` to `.prettierignore`
 - [#6520](https://github.com/mruby/mruby/pull/6520) pre-commit: autoupdate and update node LTS version
 - [#6521](https://github.com/mruby/mruby/pull/6521) Add codespell config file `.codespellrc`
 - [#6522](https://github.com/mruby/mruby/pull/6522) gha: label more files
 - [#6523](https://github.com/mruby/mruby/pull/6523) add `rand(Range)` and unify implementations of `Random#rand` and `Kernel#rand`
 - [#6524](https://github.com/mruby/mruby/pull/6524) Fix Kernel#p when no argument
 - [#6525](https://github.com/mruby/mruby/pull/6525) Skip adding empty input to mirb history
 - [#6526](https://github.com/mruby/mruby/pull/6526) Add build config for Luckfox Pico embedded SBC
 - [#6528](https://github.com/mruby/mruby/pull/6528) misc: fix spelling
 - [#6530](https://github.com/mruby/mruby/pull/6530) Revert "class.c (find_visibility_scope): when callinfo returns, \*ep == NULL; #6512"
 - [#6531](https://github.com/mruby/mruby/pull/6531) Improve method table performance by rehashing at 75% load factor
 - [#6532](https://github.com/mruby/mruby/pull/6532) Reverted method table optimizations to prioritize memory savings
 - [#6533](https://github.com/mruby/mruby/pull/6533) Fix calling `extended` callback
 - [#6534](https://github.com/mruby/mruby/pull/6534) Add descriptive comment to mrb_read_float function
 - [#6535](https://github.com/mruby/mruby/pull/6535) Added descriptive comments for functions/macros in src/mempool.c
 - [#6536](https://github.com/mruby/mruby/pull/6536) Add descriptive comments to public functions in src/debug.c
 - [#6537](https://github.com/mruby/mruby/pull/6537) Updated comments in `cdump.c` to remove the `@brief` tag
 - [#6539](https://github.com/mruby/mruby/pull/6539) Add descriptive comments for functions in src/load.c
 - [#6540](https://github.com/mruby/mruby/pull/6540) Add descriptive comments to MRB_API functions in object.c
 - [#6541](https://github.com/mruby/mruby/pull/6541) Add descriptive comments for MRB_API functions in src/array.c
 - [#6542](https://github.com/mruby/mruby/pull/6542) Add descriptive comments to MRB_API functions in src/symbol.c
 - [#6543](https://github.com/mruby/mruby/pull/6543) Add descriptive comments to several functions in src/dump.c
 - [#6544](https://github.com/mruby/mruby/pull/6544) Fix build strings that must be mutable
 - [#6545](https://github.com/mruby/mruby/pull/6545) Add descriptive comments for MRB_API functions in src/class.c
 - [#6548](https://github.com/mruby/mruby/pull/6548) Add descriptive comments to MRB_API functions in src/etc.c
 - [#6549](https://github.com/mruby/mruby/pull/6549) Add descriptive comments to kernel functions
 - [#6550](https://github.com/mruby/mruby/pull/6550) Add descriptive comments for MRB_API functions in src/proc.c
 - [#6551](https://github.com/mruby/mruby/pull/6551) Add descriptive comments for MRB_API functions in src/state.c
 - [#6552](https://github.com/mruby/mruby/pull/6552) Fix: Correct placement of comments in src/variable.c
 - [#6553](https://github.com/mruby/mruby/pull/6553) Add descriptive comments for MRB_API functions in src/vm.c
 - [#6555](https://github.com/mruby/mruby/pull/6555) `mrb_mt_foreach()` needs to update the pointer at each loop
 - [#6556](https://github.com/mruby/mruby/pull/6556) `iv_foreach()` needs to update the pointer at each loop
 - [#6560](https://github.com/mruby/mruby/pull/6560) Refactor: Improve Set GC marking and freeing
 - [#6561](https://github.com/mruby/mruby/pull/6561) pre-commit updates and fix prettier entrypoint
 - [#6562](https://github.com/mruby/mruby/pull/6562) misc: fix spelling word case
 - [#6563](https://github.com/mruby/mruby/pull/6563) pre-commit add rubocop with one rule spaces for indentation
 - [#6564](https://github.com/mruby/mruby/pull/6564) Remove jumanjihouse pre-commit hooks no longer maintained
 - [#6565](https://github.com/mruby/mruby/pull/6565) Rubocop: fix target Ruby version; add two more cops; fix lint error
 - [#6566](https://github.com/mruby/mruby/pull/6566) Removed unreferenced variables in `CrossBuild#run_bintest`
 - [#6567](https://github.com/mruby/mruby/pull/6567) Avoid array object creation in `cmd_bin` method in bintest
 - [#6568](https://github.com/mruby/mruby/pull/6568) mruby-bin-debugger depends on mruby-bin-mrbc in bintest
 - [#6569](https://github.com/mruby/mruby/pull/6569) sed s/Mruby/MRuby/g
 - [#6571](https://github.com/mruby/mruby/pull/6571) Update limitations.md to add behavior on small hash
 - [#6572](https://github.com/mruby/mruby/pull/6572) Add Claude Code GitHub Workflow
 - [#6573](https://github.com/mruby/mruby/pull/6573) pre-commit fixes and updates
 - [#6574](https://github.com/mruby/mruby/pull/6574) Support initializing structs via keyword arguments
 - [#6575](https://github.com/mruby/mruby/pull/6575) Fix typo in file time methods
 - [#6581](https://github.com/mruby/mruby/pull/6581) Merge `mrb_obj_iv_inspect()` into `mrb_obj_inspect()`
 - [#6582](https://github.com/mruby/mruby/pull/6582) Stricter type tag in `mrb_obj_alloc()`
 - [#6583](https://github.com/mruby/mruby/pull/6583) Add fallback to local build_config.rb before using default configuration
 - [#6585](https://github.com/mruby/mruby/pull/6585) Fix typo in mruby3.2 docs
 - [#6586](https://github.com/mruby/mruby/pull/6586) Makefile: refactor add docs and add command line `help` target
 - [#6587](https://github.com/mruby/mruby/pull/6587) Add Set#hash tests
 - [#6588](https://github.com/mruby/mruby/pull/6588) Add CodeQL Analysis for GitHub Actions
 - [#6589](https://github.com/mruby/mruby/pull/6589) Add pre-commit hook `check-zip-file-is-not-committed`
 - [#6591](https://github.com/mruby/mruby/pull/6591) mruby-eval fix license link in README
 - [#6593](https://github.com/mruby/mruby/pull/6593) README: Add Contributors Avatars, Star History, Table of Contents
 - [#6598](https://github.com/mruby/mruby/pull/6598) Fix heap buffer overflow in `#method_missing`
 - [#6599](https://github.com/mruby/mruby/pull/6599) pre-commit: run `markdown-link-check`, `oxipng`, `prettier` manually
 - [#6600](https://github.com/mruby/mruby/pull/6600) `dreamcast_shelf build config`: update to use KallistiOS wrappers
 - [#6601](https://github.com/mruby/mruby/pull/6601) fix: skip local build_config.rb when working in MRUBY_ROOT
 - [#6602](https://github.com/mruby/mruby/pull/6602) Improved iseq annotations for `new` and `!=`
 - [#6604](https://github.com/mruby/mruby/pull/6604) pre-commit config updates
 - [#6607](https://github.com/mruby/mruby/pull/6607) fix bigint on raspberry pi
 - [#6610](https://github.com/mruby/mruby/pull/6610) Extract golden ratio prime into constant
 - [#6614](https://github.com/mruby/mruby/pull/6614) Fix uninitialized variable in io_gets causing segmentation fault
 - [#6617](https://github.com/mruby/mruby/pull/6617) Fix various minor problems and speed up build
 - [#6618](https://github.com/mruby/mruby/pull/6618) Stop generating unnecessary C++ files in mruby-bin-mruby
 - [#6621](https://github.com/mruby/mruby/pull/6621) Set up all GEMS before mruby core tasks definition
 - [#6624](https://github.com/mruby/mruby/pull/6624) Fixed wrong `MRuby::Build.current` at the top level of `mrbgem.rake`
 - [#6628](https://github.com/mruby/mruby/pull/6628) Revert `File.absolute_path` logic
 - [#6629](https://github.com/mruby/mruby/pull/6629) pre-commit update
 - [#6631](https://github.com/mruby/mruby/pull/6631) Revert "Rakefile: make the whole thing parallel unless SERIAL=1"
 - [#6633](https://github.com/mruby/mruby/pull/6633) Fix a heap-buffer-overflow in str strip! methods
 - [#6643](https://github.com/mruby/mruby/pull/6643) Fix crash caused by an incorrect node type check in `codegen_masgn`
 - [#6651](https://github.com/mruby/mruby/pull/6651) Address stack-use-after-return in the mruby bigint implementation
 - [#6653](https://github.com/mruby/mruby/pull/6653) Improve HAL-related components for MinGW
 - [#6655](https://github.com/mruby/mruby/pull/6655) Preventing Memory Leaks in `Array#__combination_init`
 - [#6656](https://github.com/mruby/mruby/pull/6656) Fix integer overflow in allocation size calculation
 - [#6663](https://github.com/mruby/mruby/pull/6663) Added the `kh_is_end()` macro function
 - [#6665](https://github.com/mruby/mruby/pull/6665) Fixed use-after-free with `Set#join`
 - [#6670](https://github.com/mruby/mruby/pull/6670) Arranging VM dispatch macros
 - [#6673](https://github.com/mruby/mruby/pull/6673) Adjust broken license links; clean up Markdown
 - [#6677](https://github.com/mruby/mruby/pull/6677) gha: run pre-commit with `--color=always`
 - [#6678](https://github.com/mruby/mruby/pull/6678) Put ls-lint and pre-commit in separate workflow files
 - [#6679](https://github.com/mruby/mruby/pull/6679) pre-commit autoupdate; update node and prettier
 - [#6681](https://github.com/mruby/mruby/pull/6681) Add Cosmopolitan Libc build configuration
 - [#6689](https://github.com/mruby/mruby/pull/6689) docs: fix pre-commit manual hooks; fix link
 - [#6694](https://github.com/mruby/mruby/pull/6694) Fix mirb build under Cosmopolitan
 - [#6695](https://github.com/mruby/mruby/pull/6695) Dependabot: add a cooldown period for new releases
 - [#6696](https://github.com/mruby/mruby/pull/6696) Fix parse error with required kwargs and omitted parens
 - [#6699](https://github.com/mruby/mruby/pull/6699) Fix mruby-task for PicoRuby Integration
 - [#6700](https://github.com/mruby/mruby/pull/6700) Fix float/double pack/unpack on s390x
 - [#6706](https://github.com/mruby/mruby/pull/6706) Refactor task class to use symbol IDs
 - [#6708](https://github.com/mruby/mruby/pull/6708) `initialize_copy` and `respond_to_missing?` defined as private
 - [#6709](https://github.com/mruby/mruby/pull/6709) Add the `MRB_ENSURE()` macro
 - [#6711](https://github.com/mruby/mruby/pull/6711) Fix out of bounds read and write in IO.select
 - [#6714](https://github.com/mruby/mruby/pull/6714) Fix OP_DEBUG operand type and add NULL check for debug_op_hook
 - [#6716](https://github.com/mruby/mruby/pull/6716) Fixes identity for proc object
 - [#6717](https://github.com/mruby/mruby/pull/6717) Fix mruby-task: wrapping by critical section and setting initial task receiver
 - [#6718](https://github.com/mruby/mruby/pull/6718) Add installation instructions for conda and Homebrew
 - [#6723](https://github.com/mruby/mruby/pull/6723) Add `RInteger` and `RFloat` to `RVALUE`
 - [#6727](https://github.com/mruby/mruby/pull/6727) Language documentation: update wording of "overloading" section
 - [#6729](https://github.com/mruby/mruby/pull/6729) Simplifying dependency addition for gensym task
 - [#6730](https://github.com/mruby/mruby/pull/6730) Simplifying presym file generation actions
 - [#6733](https://github.com/mruby/mruby/pull/6733) Include `mruby/presym.h` for all source files
 - [#6734](https://github.com/mruby/mruby/pull/6734) Chunk array literals at 64 elements to reduce register pressure
 - [#6735](https://github.com/mruby/mruby/pull/6735) Prevent full recompilation without changes to presym file
 - [#6739](https://github.com/mruby/mruby/pull/6739) Fix MSYS2 build error with drive letters
 - [#6743](https://github.com/mruby/mruby/pull/6743) Chunk `%w()` and `%i()` literals to reduce register pressure
 - [#6744](https://github.com/mruby/mruby/pull/6744) Raise `NoMatchingPatternError` in `case`/`in` without `else`
 - [#6747](https://github.com/mruby/mruby/pull/6747) Correctly handle empty hash as default named argument
 - [#6749](https://github.com/mruby/mruby/pull/6749) Fix microcontroller profile
 - [#6750](https://github.com/mruby/mruby/pull/6750) Fix out-of-bounds read and divide-by-zero in `Array#product`
 - [#6752](https://github.com/mruby/mruby/pull/6752) Fix `attr_reader`-generated methods accepting extra arguments
 - [#6753](https://github.com/mruby/mruby/pull/6753) Further optimize `Array#product`
 - [#6754](https://github.com/mruby/mruby/pull/6754) Mark `attr_reader` procs as noarg
 - [#6755](https://github.com/mruby/mruby/pull/6755) Reload `ci` after `mrb_hash_delete_key()` in keyword argument handling
 - [#6756](https://github.com/mruby/mruby/pull/6756) Avoid impact of object modifications caused by `mrb_vm_exec()` calls
 - [#6758](https://github.com/mruby/mruby/pull/6758) Don't assign result of `mrb_funcall()` directly to `regs`
 - [#6759](https://github.com/mruby/mruby/pull/6759) Define `mrb_bigint_p()` always
 - [#6761](https://github.com/mruby/mruby/pull/6761) Fix `mrb_gc_unregister()` to remove all matching entries
 - [#6762](https://github.com/mruby/mruby/pull/6762) Write generated test C files atomically to avoid build race condition
 - [#6765](https://github.com/mruby/mruby/pull/6765) Fix `Lazy#flat_map` to handle non-enumerable block return values
 - [#6767](https://github.com/mruby/mruby/pull/6767) Allow compound statement in parenthesized argument context
 - [#6780](https://github.com/mruby/mruby/pull/6780) Fix `String#prepend` with self-referencing arguments
 - [#6781](https://github.com/mruby/mruby/pull/6781) Protect `sprintf` format string from mutation during callbacks
 - [#6783](https://github.com/mruby/mruby/pull/6783) Pin GitHub Actions workflows to commit hashes
 # Security Fixes
 - Buffer overflow in bigint uadd ([3f2611e](https://github.com/mruby/mruby/commit/3f2611e))
 - Stack buffer overflow in Montgomery reduction ([edce0a3](https://github.com/mruby/mruby/commit/edce0a3))
 - Buffer overflow in pack_uu encoding ([2993302](https://github.com/mruby/mruby/commit/2993302))
 - Buffer overflow in IO#ungetc ([01ab2ff](https://github.com/mruby/mruby/commit/01ab2ff))
 - Heap-buffer-overflow in pattern alternation codegen ([eea9e30](https://github.com/mruby/mruby/commit/eea9e30))
 - Out of bounds read and write in IO.select ([44831711](https://github.com/mruby/mruby/commit/44831711))
 - Off-by-one in bounds check for symbol names and pool strings in load.c ([b3b8c01](https://github.com/mruby/mruby/commit/b3b8c01))
 - Use-after-free in Set operations ([a6b55e7](https://github.com/mruby/mruby/commit/a6b55e7))
 - Use-after-free in Array set operations ([729b84c](https://github.com/mruby/mruby/commit/729b84c))
 - Use-after-free in Set#join ([0e653eb](https://github.com/mruby/mruby/commit/0e653eb))
 - Use-after-realloc in Array#sort! ([eb39897](https://github.com/mruby/mruby/commit/eb39897))
 - Heap-use-after-free in insertion_sort ([099d2c47](https://github.com/mruby/mruby/commit/099d2c47))
 - Integer overflow in str_check_length ([6afff1c3](https://github.com/mruby/mruby/commit/6afff1c3))
 - Integer overflow in Integer#lcm ([070bef24](https://github.com/mruby/mruby/commit/070bef24))
 - Heap buffer overflow in `#method_missing` ([550d10a](https://github.com/mruby/mruby/commit/550d10a))
 - Out-of-bounds read and divide-by-zero in `Array#product` ([8441eaf](https://github.com/mruby/mruby/commit/8441eaf))
 - Heap buffer overflow in `String#prepend` with self-referencing arguments ([18ba026](https://github.com/mruby/mruby/commit/18ba026))
 - Use-after-free in `sprintf` via `to_s` callback mutating format string ([48fc422](https://github.com/mruby/mruby/commit/48fc422))
 - Multiple memory leak fixes in bigint, Set, Array, and Task gems
@@ -138,8 +138,8 @@
 /* turn off generational GC by default */
 //#define MRB_GC_TURN_OFF_GENERATIONAL
-/* default size of khash table bucket */
+/* initial size of khash table bucket */
-//#define KHASH_DEFAULT_SIZE 32
+//#define KHASH_INITIAL_SIZE 32
 /* allocated memory address alignment */
 //#define POOL_ALIGNMENT 4
@@ -172,6 +172,13 @@
 #define MRB_SYMBOL_LINEAR_THRESHOLD 256
 #endif
 /* Maximum number of dynamic symbols (created at runtime via to_sym etc.)
   Presyms, inline symbols, and mrb_intern_static symbols are excluded.
   Set to 0 to disable the limit. */
 #ifndef MRB_SYMBOL_MAX
 #define MRB_SYMBOL_MAX 4096
 #endif
 /* obsolete configurations */
 #if defined(DISABLE_STDIO) || defined(MRB_DISABLE_STDIO)
 # define MRB_NO_STDIO
@@ -208,8 +215,8 @@
 #  define MRB_NO_METHOD_CACHE
 # endif
-# ifndef KHASH_DEFAULT_SIZE
+# ifndef KHASH_INITIAL_SIZE
-#  define KHASH_DEFAULT_SIZE 16
+#  define KHASH_INITIAL_SIZE 16
 # endif
 # ifndef MRB_HEAP_PAGE_SIZE
@@ -113,6 +113,8 @@
 #include "mrbconf.h"
 typedef struct mrb_state mrb_state;
 #include <mruby/common.h>
 #include <mruby/value.h>
 #include <mruby/gc.h>
@@ -156,8 +158,6 @@ typedef uint32_t mrb_aspec;
 typedef struct mrb_irep mrb_irep;
 struct mrb_state;
 #ifndef MRB_FIXED_STATE_ATEXIT_STACK_SIZE
 #define MRB_FIXED_STATE_ATEXIT_STACK_SIZE 5
 #endif
@@ -224,7 +224,7 @@ mrb_static_assert_powerof2(MRB_METHOD_CACHE_SIZE);
 * @param self The self object
 * @return [mrb_value] The function's return value
 */
-typedef mrb_value (*mrb_func_t)(struct mrb_state *mrb, mrb_value self);
+typedef mrb_value (*mrb_func_t)(mrb_state *mrb, mrb_value self);
 typedef struct {
  uint32_t flags;                       /* method flags (no symbol packed) */
@@ -243,9 +243,26 @@ struct mrb_cache_entry {
 };
 #endif
 #ifdef MRB_CONST_CACHE_SIZE
 # undef MRB_NO_CONST_CACHE
 mrb_static_assert_powerof2(MRB_CONST_CACHE_SIZE);
 #else
 /* default constant cache size: 64 */
 /* cache size needs to be power of 2 */
 # define MRB_CONST_CACHE_SIZE (1<<6)
 #endif
 #ifndef MRB_NO_CONST_CACHE
 struct mrb_const_cache_entry {
  const struct mrb_irep *irep;
  mrb_sym sym;
  mrb_value value;
 };
 #endif
 struct mrb_jmpbuf;
-typedef void (*mrb_atexit_func)(struct mrb_state*);
+typedef void (*mrb_atexit_func)(mrb_state*);
 #ifdef MRB_USE_TASK_SCHEDULER
 struct mrb_task;
@@ -257,10 +274,12 @@ typedef struct mrb_task_state {
  volatile mrb_bool switching;      /* Context switch pending flag */
  struct mrb_task *main_task;       /* Main task wrapper for root context */
  uint8_t scheduler_lock;           /* Lock counter for synchronous execution */
  mrb_bool loop_running;            /* Active mrb_task_run loop flag */
  mrb_bool exception_as_result;     /* Return unhandled task exceptions as values */
 } mrb_task_state;
 #endif
-typedef struct mrb_state {
+struct mrb_state {
  struct mrb_jmpbuf *jmp;
  struct mrb_context *c;
@@ -297,22 +316,28 @@ typedef struct mrb_state {
  struct mrb_cache_entry cache[MRB_METHOD_CACHE_SIZE];
 #endif
 #ifndef MRB_NO_CONST_CACHE
  struct mrb_const_cache_entry const_cache[MRB_CONST_CACHE_SIZE];
 #endif
  mrb_sym symidx;
  const char **symtbl;
  uint8_t *sym_flags;                     /* per-symbol flags (SYM_FL_*) */
  size_t symcapa;
  struct mrb_sym_hash_table *symhash;
  void *sym_pool;
  mrb_sym dynamic_sym_count;              /* count of dynamic (GC-candidate) symbols */
 #ifndef MRB_USE_ALL_SYMBOLS
  char symbuf[8];                         /* buffer for small symbol names */
 #endif
 #ifdef MRB_USE_DEBUG_HOOK
-  void (*code_fetch_hook)(struct mrb_state* mrb, const struct mrb_irep *irep, const mrb_code *pc, mrb_value *regs);
+  void (*code_fetch_hook)(mrb_state* mrb, const struct mrb_irep *irep, const mrb_code *pc, mrb_value *regs);
-  void (*debug_op_hook)(struct mrb_state* mrb, const struct mrb_irep *irep, const mrb_code *pc, mrb_value *regs);
+  void (*debug_op_hook)(mrb_state* mrb, const struct mrb_irep *irep, const mrb_code *pc, mrb_value *regs);
 #endif
 #ifdef MRB_BYTECODE_DECODE_OPTION
-  mrb_code (*bytecode_decoder)(struct mrb_state* mrb, mrb_code code);
+  mrb_code (*bytecode_decoder)(mrb_state* mrb, mrb_code code);
 #endif
  struct RClass *eException_class;
@@ -339,7 +364,7 @@ typedef struct mrb_state {
 #ifdef MRB_USE_TASK_SCHEDULER
  mrb_task_state task;                    /* Task scheduler state */
 #endif
-} mrb_state;
+};
 /**
 * Defines a new class.
@@ -1159,6 +1184,21 @@ MRB_API mrb_value mrb_funcall_id(mrb_state *mrb, mrb_value val, mrb_sym mid, mrb
 * @see mrb_funcall
 */
 MRB_API mrb_value mrb_funcall_argv(mrb_state *mrb, mrb_value val, mrb_sym name, mrb_int argc, const mrb_value *argv);
 /*
 * Convenience wrappers for `mrb_funcall_argv` with a fixed argument count.
 * Avoids the 16-slot fixed argv buffer used by the variadic `mrb_funcall_id`.
 */
 MRB_INLINE mrb_value
 mrb_funcall_argv1(mrb_state *mrb, mrb_value val, mrb_sym name, mrb_value a1)
 {
  return mrb_funcall_argv(mrb, val, name, 1, &a1);
 }
 MRB_INLINE mrb_value
 mrb_funcall_argv2(mrb_state *mrb, mrb_value val, mrb_sym name, mrb_value a1, mrb_value a2)
 {
  const mrb_value argv[] = { a1, a2 };
  return mrb_funcall_argv(mrb, val, name, 2, argv);
 }
 /**
 * Call existing Ruby functions with a block.
 */
@@ -1284,6 +1324,11 @@ MRB_API void mrb_method_cache_clear(mrb_state *mrb);
 #else
 #define mrb_method_cache_clear(mrb) ((void)0)
 #endif
 #ifndef MRB_NO_CONST_CACHE
 MRB_API void mrb_const_cache_clear(mrb_state *mrb);
 #else
 #define mrb_const_cache_clear(mrb) ((void)0)
 #endif
 /**
 * Check if mrb_open() failed
@@ -20,7 +20,17 @@ typedef struct mrb_shared_array {
  mrb_value *ptr;
 } mrb_shared_array;
-#if defined(MRB_32BIT) && defined(MRB_NO_BOXING) && (!defined(MRB_USE_FLOAT32) || defined(MRB_INT64)) && !defined(MRB_ARY_NO_EMBED)
+/* On 32-bit platforms whose ABI gives 8-byte members 8-byte alignment
   (ARM, MIPS, xtensa, ...), an embedded mrb_value array forces 8-byte
   alignment of the inner union, padding the heap-form layout and
   inflating struct size past the 5-word RVALUE limit.  Disable embedding
   whenever mrb_value contains an 8-byte aligned member: nan-boxing
   (uint64_t), or no-boxing with int64_t/double inside the union. */
 #if defined(MRB_32BIT) && \
    (defined(MRB_NAN_BOXING) || \
     (defined(MRB_NO_BOXING) && \
      (!defined(MRB_USE_FLOAT32) || defined(MRB_INT64)))) && \
    !defined(MRB_ARY_NO_EMBED)
 # define MRB_ARY_NO_EMBED
 #endif
@@ -57,7 +67,7 @@ struct RArray {
 #define ARY_UNSET_EMBED_FLAG(a) (void)0
 #define ARY_EMBED_LEN(a) 0
 #define ARY_SET_EMBED_LEN(a,len) (void)0
-#define ARY_EMBED_PTR(a) 0
+#define ARY_EMBED_PTR(a) ((mrb_value*)NULL)
 #else
 #define MRB_ARY_EMBED_MASK  7
 #define ARY_EMBED_P(a) ((a)->flags & MRB_ARY_EMBED_MASK)
@@ -71,6 +81,7 @@ struct RArray {
 #define ARY_PTR(a) (ARY_EMBED_P(a)?ARY_EMBED_PTR(a):(a)->as.heap.ptr)
 #define RARRAY_LEN(a) ARY_LEN(RARRAY(a))
 #define RARRAY_PTR(a) ARY_PTR(RARRAY(a))
 #define RARRAY_GETMEM(a, ptr, len) ARY_GETMEM(RARRAY(a), ptr, len)
 #define ARY_SET_LEN(a,n) do {\
  if (ARY_EMBED_P(a)) {\
    mrb_assert((n) <= MRB_ARY_EMBED_LEN_MAX); \
@@ -84,6 +95,17 @@ struct RArray {
 #define ARY_SHARED_P(a) ((a)->flags & MRB_ARY_SHARED)
 #define ARY_SET_SHARED_FLAG(a) ((a)->flags |= MRB_ARY_SHARED)
 #define ARY_UNSET_SHARED_FLAG(a) ((a)->flags &= ~MRB_ARY_SHARED)
 #define ARY_GETMEM(a, ptr, len) do { \
  struct RArray *MRB_UNIQNAME(_a_) = (a); \
  if (ARY_EMBED_P(MRB_UNIQNAME(_a_))) { \
    (len) = ARY_EMBED_LEN(MRB_UNIQNAME(_a_)); \
    (ptr) = ARY_EMBED_PTR(MRB_UNIQNAME(_a_)); \
  } \
  else { \
    (len) = MRB_UNIQNAME(_a_)->as.heap.len; \
    (ptr) = MRB_UNIQNAME(_a_)->as.heap.ptr; \
  } \
 } while (0)
 MRB_API void mrb_ary_modify(mrb_state*, struct RArray*);
 MRB_API mrb_value mrb_ary_dup(mrb_state*, mrb_value ary);
@@ -103,7 +103,8 @@ mrb_unboxed_type(mrb_value o)
 {
  if (!mrb_float_p(o) && mrb_nb_tt(o) == MRB_NANBOX_TT_OBJECT && o.u != 0) {
    return ((struct RBasic*)(uintptr_t)o.u)->tt;
-  } else {
+  }
  else {
    return MRB_TT_FALSE;
  }
 }
@@ -150,7 +151,7 @@ mrb_nan_boxing_value_int(mrb_value v)
 #define SET_TRUE_VALUE(r) NANBOX_SET_MISC_VALUE(r, MRB_TT_TRUE, 1)
 #define SET_BOOL_VALUE(r,b) NANBOX_SET_MISC_VALUE(r, (b) ? MRB_TT_TRUE : MRB_TT_FALSE, 1)
 #ifdef MRB_INT64
-MRB_API mrb_value mrb_boxing_int_value(struct mrb_state*, mrb_int);
+MRB_API mrb_value mrb_boxing_int_value(mrb_state*, mrb_int);
 #define SET_INT_VALUE(mrb, r, n) ((r) = mrb_boxing_int_value(mrb, n))
 #else
 #define SET_INT_VALUE(mrb, r, n) SET_FIXNUM_VALUE(r, n)
@@ -165,11 +165,11 @@ mrb_val_union(mrb_value v)
  return x;
 }
-MRB_API mrb_value mrb_word_boxing_cptr_value(struct mrb_state*, void*);
+MRB_API mrb_value mrb_word_boxing_cptr_value(mrb_state*, void*);
 #ifndef MRB_NO_FLOAT
-MRB_API mrb_value mrb_word_boxing_float_value(struct mrb_state*, mrb_float);
+MRB_API mrb_value mrb_word_boxing_float_value(mrb_state*, mrb_float);
 #endif
-MRB_API mrb_value mrb_boxing_int_value(struct mrb_state*, mrb_int);
+MRB_API mrb_value mrb_boxing_int_value(mrb_state*, mrb_int);
 #if WORDBOX_IMMEDIATE_MASK == 0x3
 #define mrb_immediate_p(o) ((o).w & WORDBOX_IMMEDIATE_MASK || (o).w <= MRB_Qundef)
@@ -266,9 +266,11 @@ mrb_unboxed_type(mrb_value o)
 {
  if (mrb_nil_p(o)) {
    return MRB_TT_FALSE;
-  } else if ((o.w & WORDBOX_IMMEDIATE_MASK) == 0) {
+  }
  else if ((o.w & WORDBOX_IMMEDIATE_MASK) == 0) {
    return mrb_val_union(o).bp->tt;
-  } else {
+  }
  else {
    return MRB_TT_FALSE;
  }
 }
@@ -100,10 +100,13 @@ void mrb_mc_clear_by_class(mrb_state *mrb, struct RClass* c);
 typedef int (mrb_mt_foreach_func)(mrb_state*,mrb_sym,mrb_method_t,void*);
 MRB_API void mrb_mt_foreach(mrb_state*, struct RClass*, mrb_mt_foreach_func*, void*);
-/* ROM method table types for static method registration */
+/* ROM method table types for static method registration.
 * NOTE: `func` is kept as the first union member so that positional
 * aggregate initialization in MRB_MT_ENTRY works without C99
 * designated initializers (required for legacy C++ compilers). */
 union mrb_mt_ptr {
  const struct RProc *proc;
  mrb_func_t func;
  const struct RProc *proc;
 };
 /* entry combining function pointer, symbol key, and flags */
@@ -128,7 +131,7 @@ typedef struct mrb_mt_tbl {
 /* ROM table entry: 3rd param is MRB_ARGS_*() optionally OR'd with MRB_MT_PRIVATE. */
 #define MRB_MT_ENTRY(fn, sym, flags) \
-  { { .func = (fn) }, (sym), (flags) | MRB_MT_FUNC }
+  { { (fn) }, (sym), (flags) | MRB_MT_FUNC }
 #define MRB_MT_ASPEC(flags) ((mrb_aspec)((flags) & 0xffffff))
 /* "removed" tombstone: MRB_MT_FUNC flag set with NULL function pointer.
@@ -134,6 +134,7 @@ struct mrb_parser_state {
  mrb_sym* filename_table;
  uint16_t filename_table_length;
  uint16_t current_filename_index;
  uint16_t prev_file_lineno;    /* saved lineno before partial_hook file switch */
  /* Variable-sized node management */
  mrb_ast_node *nvars;
@@ -37,7 +37,14 @@ MRB_API mrb_value mrb_exc_new_str(mrb_state *mrb, struct RClass* c, mrb_value st
 #define mrb_exc_new_lit(mrb, c, lit) mrb_exc_new_str(mrb, c, mrb_str_new_lit(mrb, lit))
 MRB_API mrb_noreturn void mrb_no_method_error(mrb_state *mrb, mrb_sym id, mrb_value args, const char *fmt, ...);
-#if defined(MRB_NAN_BOXING) || defined(MRB_WORD_BOXING) || defined(MRB_64BIT)
+/* On 32-bit platforms whose ABI gives uint64_t/double 8-byte alignment
   (ARM, MIPS, PowerPC, xtensa, ...), embedding mrb_value directly in
   RBreak forces 8-byte alignment that pushes the struct past the 5-word
   RVALUE budget via padding.  Store the value bits as a uint32_t array
   (4-byte aligned) to dodge that padding.  Word-boxing's mrb_value is
   just a uintptr_t with no over-alignment, and 64-bit platforms have no
   alignment gap to begin with, so neither needs the workaround. */
 #if defined(MRB_64BIT) || defined(MRB_WORD_BOXING)
 #undef MRB_USE_RBREAK_VALUE_UNION
 #else
 #define MRB_USE_RBREAK_VALUE_UNION 1
@@ -45,7 +52,8 @@ MRB_API mrb_noreturn void mrb_no_method_error(mrb_state *mrb, mrb_sym id, mrb_va
 /*
 *  flags:
- *      0..7:   enum mrb_vtype (only when defined MRB_USE_RBREAK_VALUE_UNION)
+ *      0..7:   enum mrb_vtype (only when MRB_USE_RBREAK_VALUE_UNION and
 *              !MRB_NAN_BOXING; nan-boxing encodes the type in the bits)
 *      8..10:  RBREAK_TAGs in src/vm.c (otherwise, set to 0)
 */
 struct RBreak {
@@ -53,11 +61,11 @@ struct RBreak {
  uintptr_t ci_break_index; // The top-level ci index to break. One before the return destination.
 #ifndef MRB_USE_RBREAK_VALUE_UNION
  mrb_value val;
 #elif defined(MRB_NAN_BOXING)
  /* nan-boxing: mrb_value is a single 64-bit word (type encoded in NaN bits) */
  uint32_t value[sizeof(mrb_value) / sizeof(uint32_t)];
 #else
-  /* Store value as uint32_t words instead of union mrb_value_union
+  /* no-boxing: store only the union bits; tt goes in flags */
     to avoid 8-byte alignment of int64_t/double on 32-bit platforms
     (e.g., ARM, MIPS, PowerPC) which would inflate struct size beyond
     the 5-word RVALUE limit due to padding. */
  uint32_t value[sizeof(union mrb_value_union) / sizeof(uint32_t)];
 #endif
 };
@@ -65,6 +73,19 @@ struct RBreak {
 #ifndef MRB_USE_RBREAK_VALUE_UNION
 #define mrb_break_value_get(brk) ((brk)->val)
 #define mrb_break_value_set(brk, v) ((brk)->val = v)
 #elif defined(MRB_NAN_BOXING)
 static inline mrb_value
 mrb_break_value_get(struct RBreak *brk)
 {
  mrb_value val;
  memcpy(&val, brk->value, sizeof(val));
  return val;
 }
 static inline void
 mrb_break_value_set(struct RBreak *brk, mrb_value val)
 {
  memcpy(brk->value, &val, sizeof(val));
 }
 #else
 #define RBREAK_VALUE_TT_MASK ((1 << 8) - 1)
 static inline mrb_value
@@ -14,15 +14,12 @@
 */
 MRB_BEGIN_DECL
 struct mrb_state;
 #define MRB_EACH_OBJ_OK 0
 #define MRB_EACH_OBJ_BREAK 1
-typedef int (mrb_each_object_callback)(struct mrb_state *mrb, struct RBasic *obj, void *data);
+typedef int (mrb_each_object_callback)(mrb_state *mrb, struct RBasic *obj, void *data);
-void mrb_objspace_each_objects(struct mrb_state *mrb, mrb_each_object_callback *callback, void *data);
+void mrb_objspace_each_objects(mrb_state *mrb, mrb_each_object_callback *callback, void *data);
 size_t mrb_objspace_page_slot_size(void);
-MRB_API void mrb_free_context(struct mrb_state *mrb, struct mrb_context *c);
+MRB_API void mrb_free_context(mrb_state *mrb, struct mrb_context *c);
 #ifndef MRB_GC_ARENA_SIZE
 #define MRB_GC_ARENA_SIZE 100
@@ -48,7 +45,7 @@ typedef struct mrb_gc {
  mrb_bool gray_overflow:1;        /* gray stack overflowed; needs heap rescan */
  size_t live;                     /* count of live objects */
  size_t live_after_mark;          /* old generation objects */
-  size_t threshold;                /* threshold to start GC */
+  mrb_int gc_debt;                 /* <0:credit, >0:needs GC */
  size_t oldgen_threshold;         /* threshold to kick major GC */
  mrb_gc_state state;              /* current state of gc */
  int interval_ratio;
@@ -59,6 +56,9 @@ typedef struct mrb_gc {
  mrb_bool generational  :1;       /* generational GC mode */
  mrb_bool full          :1;       /* major GC mode */
  mrb_bool out_of_memory :1;       /* out-of-memory error occurred */
  size_t step_limit;               /* 0=unlimited, >0=absolute step cap */
  size_t malloc_increase;          /* malloc bytes since last GC cycle */
  size_t malloc_threshold;         /* 0=disabled, >0=bytes to trigger GC */
 #ifdef MRB_GC_FIXED_ARENA
  struct RBasic *arena[MRB_GC_ARENA_SIZE]; /* GC protection array */
@@ -67,10 +67,16 @@ typedef struct mrb_gc {
  int arena_capa;                          /* size of protection array */
 #endif
  int arena_idx;
 #ifdef MRB_GC_STATS
  uint32_t gc_total_count;                 /* total GC invocations */
  uint32_t minor_gc_count;                 /* minor GC count */
  uint32_t major_gc_count;                 /* major GC count */
 #endif
 } mrb_gc;
-MRB_API mrb_bool mrb_object_dead_p(struct mrb_state *mrb, struct RBasic *object);
+MRB_API mrb_bool mrb_object_dead_p(mrb_state *mrb, struct RBasic *object);
-MRB_API int mrb_gc_add_region(struct mrb_state *mrb, void *start, size_t size);
+MRB_API int mrb_gc_add_region(mrb_state *mrb, void *start, size_t size);
 #define MRB_GC_RED 7
@@ -279,4 +279,7 @@ mrb_value mrb_bint_abs(mrb_state *mrb, mrb_value x);
 void mrb_task_mark_all(mrb_state *mrb);
 #endif
 /* Internal object allocation without type validation (gc.c) */
 struct RBasic* mrb_obj_alloc_core(mrb_state*, enum mrb_vtype, struct RClass*);
 #endif  /* MRUBY_INTERNAL_H */
@@ -20,7 +20,7 @@ enum irep_pool_type {
  IREP_TT_SSTR = 2,   /* string (static) */
  IREP_TT_INT32 = 1,  /* 32-bit integer */
  IREP_TT_INT64 = 3,  /* 64-bit integer */
-  IREP_TT_BIGINT = 7, /* big integer (not yet supported) */
+  IREP_TT_BIGINT = 7, /* big integer */
  IREP_TT_FLOAT = 5,  /* float (double/float) */
 };
@@ -21,7 +21,7 @@ typedef uint32_t khint_t;
 typedef khint_t khiter_t;
 #ifndef KHASH_INITIAL_SIZE
-# define KHASH_INITIAL_SIZE 8
+# define KHASH_INITIAL_SIZE 32
 #endif
 #define KHASH_MIN_SIZE 8
 #define KHASH_SMALL_LIMIT 4
@@ -102,6 +102,60 @@ struct RProc {
 #define MRB_PROC_ALIAS 8192
 #define MRB_PROC_ALIAS_P(p) (((p)->flags & MRB_PROC_ALIAS) != 0)
 /* Compressed aspec for cfunc procs (13 bits in RProc.flags).
 * Uses free bits 0-6 and 14-19 to store a compressed argument spec.
 * Layout: block(0) kdict(1) key(2-3) post(4-5) rest(6) opt(14-16) req(17-19)
 * Field widths are smaller than the full 24-bit aspec: req/opt max 7, post/key max 3.
 * Values exceeding the compressed range are clamped and rest is forced to 1. */
 #define MRB_PROC_CASPEC_MASK  0xfc07fu  /* bits 0-6 and 14-19 */
 static inline uint32_t
 mrb_proc_compress_aspec(mrb_aspec aspec)
 {
  uint32_t req   = MRB_ASPEC_REQ(aspec);
  uint32_t opt   = MRB_ASPEC_OPT(aspec);
  uint32_t rest  = MRB_ASPEC_REST(aspec);
  uint32_t post  = MRB_ASPEC_POST(aspec);
  uint32_t key   = MRB_ASPEC_KEY(aspec);
  uint32_t kdict = MRB_ASPEC_KDICT(aspec);
  uint32_t block = MRB_ASPEC_BLOCK(aspec);
  if (req > 7 || opt > 7 || post > 3 || key > 3) {
    if (req > 7) req = 7;
    if (opt > 7) opt = 7;
    if (post > 3) post = 3;
    if (key > 3) key = 3;
    rest = 1;
  }
  return block | (kdict << 1) | (key << 2) | (post << 4) | (rest << 6)
       | (opt << 14) | (req << 17);
 }
 static inline mrb_aspec
 mrb_proc_decompress_caspec(uint32_t flags)
 {
  return (((flags >> 17) & 0x7) << 18)  /* req */
       | (((flags >> 14) & 0x7) << 13)  /* opt */
       | (((flags >> 6) & 0x1) << 12)   /* rest */
       | (((flags >> 4) & 0x3) << 7)    /* post */
       | (((flags >> 2) & 0x3) << 2)    /* key */
       | (((flags >> 1) & 0x1) << 1)    /* kdict */
       | (flags & 0x1);                 /* block */
 }
 static inline void
 mrb_proc_set_cfunc_aspec(struct RProc *p, mrb_aspec aspec)
 {
  p->flags &= ~(MRB_PROC_NOARG | MRB_PROC_CASPEC_MASK);
  if (aspec == 0) {
    p->flags |= MRB_PROC_NOARG;
  }
  else {
    p->flags |= mrb_proc_compress_aspec(aspec);
  }
 }
 #define mrb_proc_ptr(v)    ((struct RProc*)(mrb_ptr(v)))
 struct RProc *mrb_proc_new(mrb_state*, const mrb_irep*);
@@ -342,6 +342,16 @@ MRB_API const char *mrb_string_value_cstr(mrb_state *mrb, mrb_value *str);
 */
 MRB_API mrb_value mrb_str_dup(mrb_state *mrb, mrb_value str);
 /**
 * Returns a frozen string object.
 * The string will be duplicated and frozen if it is not already frozen.
 *
 * @param mrb The current mruby state.
 * @param str An original Ruby string.
 * @return [mrb_value] Ruby frozen string.
 */
 MRB_API mrb_value mrb_str_dup_frozen(mrb_state *mrb, mrb_value str);
 /**
 * Returns a symbol from a passed in Ruby string.
 *
@@ -55,8 +55,6 @@ typedef uint8_t mrb_bool;
 # endif
 #endif
 struct mrb_state;
 #if defined _MSC_VER && _MSC_VER < 1800
 # define PRIo64 "llo"
 # define PRId64 "lld"
@@ -316,7 +314,11 @@ struct RCptr {
 #endif
 #define mrb_test(o)   mrb_bool(o)
 #ifndef mrb_bigint_p
 #ifdef MRB_USE_BIGINT
 #define mrb_bigint_p(o) (mrb_type(o) == MRB_TT_BIGINT)
 #else
 #define mrb_bigint_p(o) FALSE
 #endif
 #endif
 /**
@@ -326,7 +328,7 @@ struct RCptr {
 */
 #ifndef MRB_NO_FLOAT
 MRB_INLINE mrb_value
-mrb_float_value(struct mrb_state *mrb, mrb_float f)
+mrb_float_value(mrb_state *mrb, mrb_float f)
 {
  mrb_value v;
  (void) mrb;
@@ -336,7 +338,7 @@ mrb_float_value(struct mrb_state *mrb, mrb_float f)
 #endif
 MRB_INLINE mrb_value
-mrb_cptr_value(struct mrb_state *mrb, void *p)
+mrb_cptr_value(mrb_state *mrb, void *p)
 {
  mrb_value v;
  (void) mrb;
@@ -348,7 +350,7 @@ mrb_cptr_value(struct mrb_state *mrb, void *p)
 * Returns an integer in Ruby.
 */
 MRB_INLINE mrb_value
-mrb_int_value(struct mrb_state *mrb, mrb_int i)
+mrb_int_value(mrb_state *mrb, mrb_int i)
 {
  mrb_value v;
  SET_INT_VALUE(mrb, v, i);
@@ -80,7 +80,7 @@ MRB_BEGIN_DECL
 /*
 * Release year.
 */
-#define MRUBY_RELEASE_YEAR 2025
+#define MRUBY_RELEASE_YEAR 2026
 /*
 * Release month.
@@ -41,7 +41,7 @@ module MRuby
      allocf.c
      readnum.c
      readint.c
-      readfloat.c
+      fp_uscale.c
      state.c
      symbol.c
      class.c
@@ -66,7 +66,6 @@ module MRuby
      cdump.c
      codedump.c
      print.c
      fmt_fp.c
      debug.c
      etc.c
      version.c
@@ -81,7 +81,7 @@ module MRuby
    include LoadGems
    attr_accessor :name, :bins, :exts, :file_separator, :build_dir, :gem_clone_dir, :defines, :libdir_name
    attr_reader :products, :libmruby_core_objs, :libmruby_objs, :gems, :toolchains, :presym, :mrbc_build, :gem_dir_to_repo_url
-    attr_reader :install_excludes
+    attr_reader :install_excludes, :port_names
    alias libmruby libmruby_objs
@@ -138,6 +138,7 @@ module MRuby
        @mrbcfile_external = false
        @internal = internal
        @toolchains = []
        @port_names = nil
        @gem_dir_to_repo_url = {}
        # Add lambda instead of string because libdir_name or lib may be changed by user configuration
@@ -183,6 +184,30 @@ module MRuby
      @enable_debug = true
    end
    # Set target port names for this build.
    # Each gem compiles the first matching ports/<name>/ directory;
    # later names in the list act as fallbacks for gems that don't
    # ship a port for the earlier names.
    #   conf.ports :esp32
    #   conf.ports :rp2040, :posix    # use rp2040 if available, else posix
    def ports(*names)
      @port_names = names.map { |n| n.to_s }
    end
    # Returns the effective port names for this build.
    # If not explicitly set, auto-detects :posix or :win for host builds.
    def effective_ports
      return @port_names if @port_names
      if kind_of?(MRuby::CrossBuild)
        []
      elsif ENV['OS'] == 'Windows_NT' ||
            ('A'..'Z').any? { |v| Dir.exist?("#{v}:") }
        ['win']
      else
        ['posix']
      end
    end
    def disable_lock
      @enable_lock = false
    end
@@ -343,16 +343,21 @@ module MRuby
      opt = @compile_options % {funcname: funcname}
      opt << " -S" if cdump
      opt << " -s" if static
      # Have mrbc write to a private tempfile (-o) instead of stdout (-o-)
      # to avoid pipe-inheritance races with parallel rake on Windows MinGW,
      # where unrelated _pp build-progress lines from sibling workers can
      # leak into the captured stdout and corrupt the generated C file.
      tmpout = "#{out.path}.#{funcname}.mrbcout"
      opt = opt.sub(/\s-o-(?=\s|\z)/, %Q[ -o "#{filename tmpout}"])
      cmd = %["#{filename @command}" #{opt} #{filename(infiles).map{|f| %["#{f}"]}.join(' ')}]
      puts cmd if Rake.verbose
-      IO.popen(cmd, 'r') do |io|
+      unless system(cmd)
-        out.puts io.read
+        rm_f tmpout
      end
      # if mrbc execution fail, drop the file
      unless $?.success?
        rm_f out.path
        fail "Command failed with status (#{$?.exitstatus}): [#{cmd[0,42]}...]"
      end
      out.write File.binread(tmpout)
      rm_f tmpout
    end
  end
@@ -25,6 +25,7 @@ module MRuby
      alias :author= :authors=
      attr_accessor :rbfiles, :objs
      attr_reader :port_objs
      attr_writer :test_objs, :test_rbfiles
      attr_accessor :test_args, :test_preload
@@ -43,6 +44,7 @@ module MRuby
      def initialize(name, &block)
        @name = name
        @initializer = block
        @post_user_config = nil
        @version = "0.0.0"
        @dependencies = []
        @conflicts = []
@@ -59,6 +61,22 @@ module MRuby
        @rbfiles = Dir.glob("#{@dir}/mrblib/**/*.rb").sort
        @objs = srcs_to_objs("src")
        # Add platform-specific sources from the first matching
        # ports/<name>/ directory.  effective_ports is a fallback
        # chain: later names act as defaults for gems that don't ship
        # a port for the earlier names.  These objs are tracked
        # separately so List#resolve_external_hal! can drop them when
        # an external HAL provider (gem named hal-<short>-*) is loaded.
        @port_objs = []
        build.effective_ports.each do |port|
          port_dir = "#{@dir}/ports/#{port}"
          if File.directory?(port_dir)
            @port_objs = srcs_to_objs("ports/#{port}")
            @objs += @port_objs
            break
          end
        end
        @test_preload = nil # 'test/assert.rb'
        @test_args = {}
        @skip_test = false
@@ -85,6 +103,7 @@ module MRuby
        build.libmruby_objs << @objs
        instance_eval(&@build_config_initializer) if @build_config_initializer
        instance_eval(&@post_user_config) if @post_user_config
        repo_url = build.gem_dir_to_repo_url[dir]
        build.locks[repo_url]['version'] = version if repo_url
@@ -109,7 +128,8 @@ module MRuby
        if build.kind_of?(MRuby::CrossBuild)
          return %w(x86_64-w64-mingw32 i686-w64-mingw32).include?(build.host_target)
        elsif build.kind_of?(MRuby::Build)
-          return ('A'..'Z').to_a.any? { |vol| Dir.exist?("#{vol}:") }
+          return ('A'..'Z').to_a.any? { |vol| Dir.exist?("#{vol}:") } ||
                 ('a'..'z').to_a.any? { |vol| Dir.exist?("/#{vol}/") }
        end
        return false
      end
@@ -193,6 +213,19 @@ module MRuby
        end
      end
      # Register a block that runs after the user's `build.gem` block has
      # been processed.  Intended for gem authors to fill in defaults that
      # depend on user-supplied configuration (e.g. auto-detect a library
      # only if the user didn't specify which to use).
      #
      # Initialization order:
      #   1. block in `MRuby::Gem::Specification.new` (gem author)
      #   2. block in `build.gem` (user's build_config)
      #   3. block in `post_user_config` (gem author, this hook)
      def post_user_config(&block)
        @post_user_config = block
      end
      def build_settings(&blk)
        @build_settings = blk
      end
@@ -429,6 +462,28 @@ module MRuby
          self.each(&:setup)
          gemset = self.setup_dependencies(build).keys.sort
        end until gemset == gemset_prev
        resolve_external_hal!
      end
      # A gem named `hal-<short>-<conf>` is treated as the external
      # HAL provider for the gem whose name's last `-`-separated
      # segment is <short> (e.g., hal-task-glib provides the HAL for
      # mruby-task).  The target gem's ports/* sources are dropped
      # from its object list -- the matching gem supplies the
      # implementation.  Two or more matches is a build error.
      def resolve_external_hal!
        each do |target|
          next if target.port_objs.nil? || target.port_objs.empty?
          short = target.name.split('-').last
          pattern = /\Ahal-#{Regexp.escape(short)}-.+\z/
          overriders = select { |g| g != target && g.name =~ pattern }
          next if overriders.empty?
          if overriders.size > 1
            fail "Multiple HAL providers for '#{target.name}': " +
                 overriders.map(&:name).join(", ")
          end
          target.objs.reject! { |o| target.port_objs.include?(o) }
        end
      end
      def setup_build
@@ -1,7 +0,0 @@
 MRuby::Gem::Specification.new('hal-posix-dir') do |spec|
  spec.license = 'MIT'
  spec.authors = 'mruby developers'
  spec.summary = 'POSIX HAL for mruby-dir (Linux, macOS, BSD, Unix)'
  spec.add_dependency 'mruby-dir', core: 'mruby-dir'
 end
@@ -1,8 +0,0 @@
 MRuby::Gem::Specification.new('hal-posix-io') do |spec|
  spec.license = 'MIT'
  spec.author  = 'mruby developers'
  spec.summary = 'POSIX HAL for mruby-io (Linux, macOS, BSD, Unix)'
  # HAL gem depends on feature gem - brings in mruby-io automatically
  spec.add_dependency 'mruby-io', core: 'mruby-io'
 end
@@ -1,8 +0,0 @@
 MRuby::Gem::Specification.new('hal-posix-socket') do |spec|
  spec.license = 'MIT'
  spec.author  = 'mruby developers'
  spec.summary = 'POSIX HAL for mruby-socket (Linux, macOS, BSD, Unix)'
  # HAL gem depends on feature gem - brings in mruby-socket automatically
  spec.add_dependency 'mruby-socket', core: 'mruby-socket'
 end
@@ -1,102 +0,0 @@
 # hal-posix-task
 POSIX Hardware Abstraction Layer (HAL) implementation for mruby-task.
 ## Description
 Provides timer and interrupt support for the mruby-task cooperative scheduler on POSIX-compliant platforms. Uses `SIGALRM` and `setitimer()` for periodic timer ticks, and `sigprocmask()` for interrupt protection.
 ## Supported Platforms
 - Linux
 - macOS
 - BSD (FreeBSD, OpenBSD, NetBSD)
 - Other POSIX-compliant Unix systems
 ## Requirements
 - POSIX-compliant operating system
 - Signal support (`SIGALRM`, `sigaction`, `sigprocmask`)
 - Timer support (`setitimer`, `ITIMER_REAL`)
 ## Usage
 ### Explicit HAL Selection (Recommended)
 ```ruby
 MRuby::Build.new do |conf|
  # ... other configuration ...
  # Specify POSIX HAL - automatically brings in mruby-task
  conf.gem core: 'hal-posix-task'
 end
 ```
 ### Auto-detection (Development)
 ```ruby
 MRuby::Build.new do |conf|
  # ... other configuration ...
  # Auto-detects and selects hal-posix-task on POSIX platforms
  conf.gem core: 'mruby-task'
 end
 ```
 ## Implementation Details
 ### Timer Mechanism
 - Uses `setitimer(ITIMER_REAL, ...)` to generate periodic `SIGALRM` signals
 - Timer interval configured by `MRB_TICK_UNIT` (default: 4ms)
 - Signal handler calls `mrb_tick()` for all registered VM instances
 ### Interrupt Protection
 - Critical sections protected using `sigprocmask()` to block `SIGALRM`
 - Prevents race conditions during task queue modifications
 - Supports nested critical sections through signal masking
 ### Multi-VM Support
 - Supports up to `MRB_TASK_MAX_VMS` concurrent mruby VM instances (default: 8)
 - Single shared timer ticks all registered VMs
 - Per-VM task counters optimize timer usage (timer disabled when idle)
 ### Timer Optimization
 The implementation dynamically enables/disables the timer based on task state:
 - **Timer enabled** when: Multiple ready tasks OR any waiting tasks exist
 - **Timer disabled** when: Single task or all tasks dormant/suspended
 - Reduces CPU usage and power consumption when scheduler is idle
 ## Configuration
 Override these macros in your build config if needed:
 ```ruby
 conf.gem core: 'hal-posix-task' do |spec|
  # Custom tick interval (10ms instead of default 4ms)
  spec.build.defines << 'MRB_TICK_UNIT=10'
  # Custom timeslice (5 ticks instead of default 3)
  spec.build.defines << 'MRB_TIMESLICE_TICK_COUNT=5'
  # More concurrent VMs (16 instead of default 8)
  spec.build.defines << 'MRB_TASK_MAX_VMS=16'
 end
 ```
 ## Known Limitations
 - `SIGALRM` conflicts with other code using the same signal
 - Timer resolution limited by platform (typically 1-10ms)
 - Signal delivery may be delayed under heavy system load
 - Not suitable for hard real-time requirements
 ## See Also
 - `mruby-task` - Core task scheduler
 - `hal-win-task` - Windows HAL implementation
 - Task scheduler documentation: `mrbgems/mruby-task/README.md`
@@ -1,8 +0,0 @@
 MRuby::Gem::Specification.new('hal-posix-task') do |spec|
  spec.license = 'MIT'
  spec.authors = 'mruby developers'
  spec.summary = 'POSIX HAL for mruby-task (Linux, macOS, BSD, Unix)'
  # HAL gem depends on feature gem - brings in mruby-task automatically
  spec.add_dependency 'mruby-task', core: 'mruby-task'
 end
@@ -1,7 +0,0 @@
 MRuby::Gem::Specification.new('hal-win-dir') do |spec|
  spec.license = 'MIT and MIT-like license'
  spec.authors = ['mruby developers', 'Kevlin Henney']
  spec.summary = 'Windows HAL for mruby-dir'
  spec.add_dependency 'mruby-dir', core: 'mruby-dir'
 end
@@ -1,11 +0,0 @@
 MRuby::Gem::Specification.new('hal-win-io') do |spec|
  spec.license = 'MIT'
  spec.author  = 'mruby developers'
  spec.summary = 'Windows HAL for mruby-io (Windows, MinGW)'
  # HAL gem depends on feature gem - brings in mruby-io automatically
  spec.add_dependency 'mruby-io', core: 'mruby-io'
  # Link Windows socket library
  spec.linker.libraries << "ws2_32"
 end
@@ -1,12 +0,0 @@
 MRuby::Gem::Specification.new('hal-win-socket') do |spec|
  spec.license = 'MIT'
  spec.author  = 'mruby developers'
  spec.summary = 'Windows HAL for mruby-socket (Windows, MinGW)'
  # HAL gem depends on feature gem - brings in mruby-socket automatically
  spec.add_dependency 'mruby-socket', core: 'mruby-socket'
  # Link Windows socket libraries
  spec.linker.libraries << "wsock32"
  spec.linker.libraries << "ws2_32"
 end
@@ -1,176 +0,0 @@
 /*
 ** socket_hal.c - Windows HAL implementation for mruby-socket
 **
 ** See Copyright Notice in mruby.h
 **
 ** Windows implementation for socket operations using Winsock APIs.
 ** Supported platforms: Windows, MinGW
 */
 #ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x0501 // need Windows XP or later
 #endif
 #include <mruby.h>
 #include <mruby/string.h>
 #include <mruby/class.h>
 #include <mruby/error.h>
 #include "socket_hal.h"
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <windows.h>
 #include <errno.h>
 #include <string.h>
 /*
 * Socket HAL Initialization/Finalization
 */
 void
 mrb_hal_socket_init(mrb_state *mrb)
 {
  WSADATA wsaData;
  int result = WSAStartup(MAKEWORD(2, 2), &wsaData);
  if (result != NO_ERROR) {
    mrb_raise(mrb, mrb_class_get_id(mrb, MRB_SYM(RuntimeError)), "WSAStartup failed");
  }
 }
 void
 mrb_hal_socket_final(mrb_state *mrb)
 {
  (void)mrb;
  WSACleanup();
 }
 /*
 * Socket Control Operations
 */
 int
 mrb_hal_socket_set_nonblock(mrb_state *mrb, int fd, int nonblock)
 {
  (void)mrb;
  u_long mode = nonblock ? 1 : 0;
  int result = ioctlsocket(fd, FIONBIO, &mode);
  if (result != NO_ERROR) {
    return -1;
  }
  return 0;
 }
 /*
 * Address Conversion Functions
 */
 const char*
 mrb_hal_socket_inet_ntop(int af, const void *src, char *dst, size_t size)
 {
  if (af == AF_INET) {
    struct sockaddr_in in = {0};
    in.sin_family = AF_INET;
    memcpy(&in.sin_addr, src, sizeof(struct in_addr));
    if (getnameinfo((struct sockaddr*)&in, sizeof(struct sockaddr_in),
                    dst, (DWORD)size, NULL, 0, NI_NUMERICHOST) == 0) {
      return dst;
    }
    return NULL;
  }
  else if (af == AF_INET6) {
    struct sockaddr_in6 in = {0};
    in.sin6_family = AF_INET6;
    memcpy(&in.sin6_addr, src, sizeof(struct in6_addr));
    if (getnameinfo((struct sockaddr*)&in, sizeof(struct sockaddr_in6),
                    dst, (DWORD)size, NULL, 0, NI_NUMERICHOST) == 0) {
      return dst;
    }
    return NULL;
  }
  return NULL;
 }
 int
 mrb_hal_socket_inet_pton(int af, const char *src, void *dst)
 {
  struct addrinfo hints = {0};
  hints.ai_family = af;
  hints.ai_flags = AI_NUMERICHOST;
  struct addrinfo *res;
  if (getaddrinfo(src, NULL, &hints, &res) != 0) {
    return 0;  /* Invalid address */
  }
  if (res == NULL) {
    return 0;
  }
  if (af == AF_INET && res->ai_family == AF_INET) {
    memcpy(dst, &((struct sockaddr_in*)res->ai_addr)->sin_addr, sizeof(struct in_addr));
    freeaddrinfo(res);
    return 1;
  }
  else if (af == AF_INET6 && res->ai_family == AF_INET6) {
    memcpy(dst, &((struct sockaddr_in6*)res->ai_addr)->sin6_addr, sizeof(struct in6_addr));
    freeaddrinfo(res);
    return 1;
  }
  freeaddrinfo(res);
  return 0;
 }
 /*
 * Platform-Specific Socket Features
 */
 mrb_value
 mrb_hal_socket_sockaddr_un(mrb_state *mrb, const char *path, size_t pathlen)
 {
  (void)path;
  (void)pathlen;
  mrb_raise(mrb, mrb_class_get_id(mrb, MRB_SYM(NotImplementedError)),
            "sockaddr_un unsupported on Windows");
  return mrb_nil_value();
 }
 int
 mrb_hal_socket_socketpair(mrb_state *mrb, int domain, int type, int protocol, int sv[2])
 {
  (void)mrb;
  (void)domain;
  (void)type;
  (void)protocol;
  (void)sv;
  /* socketpair is not supported on Windows */
  errno = ENOSYS;
  return -1;
 }
 mrb_value
 mrb_hal_socket_unix_path(mrb_state *mrb, const char *sockaddr, size_t socklen)
 {
  (void)sockaddr;
  (void)socklen;
  mrb_raise(mrb, mrb_class_get_id(mrb, MRB_SYM(NotImplementedError)),
            "unix_path unsupported on Windows");
  return mrb_nil_value();
 }
 /*
 * Gem initialization
 */
 void
 mrb_hal_win_socket_gem_init(mrb_state *mrb)
 {
  (void)mrb;
  /* HAL interface functions are called by mruby-socket gem */
 }
 void
 mrb_hal_win_socket_gem_final(mrb_state *mrb)
 {
  (void)mrb;
  /* Cleanup handled by mrb_hal_socket_final called from mruby-socket */
 }
@@ -1,109 +0,0 @@
 # hal-win-task
 Windows Hardware Abstraction Layer (HAL) implementation for mruby-task.
 ## Description
 Provides timer and interrupt support for the mruby-task cooperative scheduler on Windows platforms. Uses multimedia timer (`timeSetEvent`/`timeKillEvent`) for periodic timer ticks, and `CRITICAL_SECTION` for interrupt protection.
 ## Supported Platforms
 - Windows 7 and later
 - Windows Server 2008 R2 and later
 - All versions with multimedia timer support
 ## Requirements
 - Windows operating system
 - Multimedia timer API (`winmm.lib`)
 - Visual C++, MinGW, or compatible compiler
 ## Usage
 ### Explicit HAL Selection (Recommended)
 ```ruby
 MRuby::Build.new do |conf|
  # ... other configuration ...
  # Specify Windows HAL - automatically brings in mruby-task
  conf.gem core: 'hal-win-task'
 end
 ```
 ### Auto-detection (Development)
 ```ruby
 MRuby::Build.new do |conf|
  # ... other configuration ...
  # Auto-detects and selects hal-win-task on Windows platforms
  conf.gem core: 'mruby-task'
 end
 ```
 ## Implementation Details
 ### Timer Mechanism
 - Uses Windows multimedia timer (`timeSetEvent`) for periodic callbacks
 - Timer interval configured by `MRB_TICK_UNIT` (default: 4ms)
 - `TIME_KILL_SYNCHRONOUS` flag ensures clean timer shutdown
 - Requests 1ms timer resolution via `timeBeginPeriod(1)`
 ### Interrupt Protection
 - Critical sections protected using `CRITICAL_SECTION` objects
 - Prevents race conditions during task queue modifications
 - `EnterCriticalSection`/`LeaveCriticalSection` used for mutual exclusion
 - Supports nested critical sections (automatic lock counting)
 ### Multi-VM Support
 - Supports up to `MRB_TASK_MAX_VMS` concurrent mruby VM instances (default: 8)
 - Single shared timer ticks all registered VMs
 - Per-VM task counters optimize timer usage (timer disabled when idle)
 - Interlocked operations (`InterlockedIncrement`/`InterlockedDecrement`) for thread safety
 ### Timer Optimization
 The implementation dynamically enables/disables the timer based on task state:
 - **Timer enabled** when: Multiple ready tasks OR any waiting tasks exist
 - **Timer disabled** when: Single task or all tasks dormant/suspended
 - Reduces CPU usage and power consumption when scheduler is idle
 ## Configuration
 Override these macros in your build config if needed:
 ```ruby
 conf.gem core: 'hal-win-task' do |spec|
  # Custom tick interval (10ms instead of default 4ms)
  spec.build.defines << 'MRB_TICK_UNIT=10'
  # Custom timeslice (5 ticks instead of default 3)
  spec.build.defines << 'MRB_TIMESLICE_TICK_COUNT=5'
  # More concurrent VMs (16 instead of default 8)
  spec.build.defines << 'MRB_TASK_MAX_VMS=16'
 end
 ```
 ## Known Limitations
 - Timer resolution typically limited to 1-2ms even with `timeBeginPeriod(1)`
 - Multimedia timers consume system resources (kernel timer objects)
 - Timer callbacks execute in separate thread context (handled internally)
 - Not suitable for hard real-time requirements
 - May interfere with other multimedia applications requesting different timer resolutions
 ## See Also
 - `mruby-task` - Core task scheduler
 - `hal-posix-task` - POSIX/Unix HAL implementation
 - Task scheduler documentation: `mrbgems/mruby-task/README.md`
 ## Build Notes
 The `winmm` library is automatically linked by the gem specification. No additional linker configuration is needed.
@@ -1,11 +0,0 @@
 MRuby::Gem::Specification.new('hal-win-task') do |spec|
  spec.license = 'MIT'
  spec.authors = 'mruby developers'
  spec.summary = 'Windows HAL for mruby-task'
  # HAL gem depends on feature gem - brings in mruby-task automatically
  spec.add_dependency 'mruby-task', core: 'mruby-task'
  # Windows multimedia timer library
  spec.linker.libraries << 'winmm'
 end
@@ -0,0 +1,74 @@
 # hw-adc - ADC peripheral interface for mruby
 This gem provides the `ADC` class for reading analog input from
 mruby. It is designed for embedded platforms such as ESP32 and
 RP2040.
 ## Architecture
 Platform-specific HAL implementations are in `ports/` directories:
 - `ports/esp32/` - ESP32 using ESP-IDF ADC oneshot driver
 - `ports/rp2040/` - RP2040 using Pico SDK ADC hardware
 ## Build Configuration
 ```ruby
 MRuby::CrossBuild.new('esp32') do |conf|
  conf.ports :esp32
  conf.gem core: 'hw-adc'
 end
 ```
 ## Ruby API
 ### ADC.new
 ```ruby
 adc = ADC.new(pin)
 ```
 - `pin` - ADC-capable GPIO pin number (Integer)
 - Raises `ArgumentError` if the pin is not valid for ADC
 ### ADC#read / ADC#read_voltage
 Read the analog value as voltage (Float).
 ```ruby
 voltage = adc.read           # => 1.65
 voltage = adc.read_voltage   # same
 ```
 ### ADC#read_raw
 Read the raw ADC value (Integer, typically 0-4095 for 12-bit).
 ```ruby
 raw = adc.read_raw   # => 2048
 ```
 ### ADC#input
 Returns the ADC input channel number assigned during initialization.
 ## HAL Interface
 To add support for a new platform, create a `ports/<name>/`
 directory and implement the following C functions declared in
 `<mruby/adc.h>`:
 ```c
 int      mrb_adc_init(uint8_t pin);
 uint32_t mrb_adc_read_raw(uint8_t input);
 float    mrb_adc_read_voltage(uint8_t input);
 ```
 - `mrb_adc_init` returns the input channel number (>= 0) on
  success, negative on error
 - `input` parameter for read functions is the value returned by
  `mrb_adc_init`
 ## License
 MIT
@@ -0,0 +1,19 @@
 #ifndef MRUBY_ADC_H
 #define MRUBY_ADC_H
 #include <stdint.h>
 #ifdef __cplusplus
 extern "C" {
 #endif
 /* HAL functions - implemented in ports/<platform>/adc.c */
 int      mrb_adc_init(uint8_t pin);
 uint32_t mrb_adc_read_raw(uint8_t input);
 float    mrb_adc_read_voltage(uint8_t input);
 #ifdef __cplusplus
 }
 #endif
 #endif /* MRUBY_ADC_H */
@@ -0,0 +1,5 @@
 MRuby::Gem::Specification.new('hw-adc') do |spec|
  spec.license = 'MIT'
  spec.authors = ['HASUMI Hitoshi', 'mruby developers']
  spec.summary = 'ADC peripheral interface'
 end
@@ -0,0 +1,7 @@
 class ADC
  def initialize(pin)
    @input = __init(pin)
  end
  attr_reader :input
 end
@@ -0,0 +1,147 @@
 #include <stdbool.h>
 #include "esp_adc/adc_oneshot.h"
 #include <mruby/adc.h>
 #define VOLTAGE_MAX 3.3f
 #define RESOLUTION  4095
 #define UNIT_NUM    2
 static adc_oneshot_unit_handle_t adc_handles[UNIT_NUM];
 static bool adc_initialized;
 static adc_unit_t
 pin_to_unit(uint8_t pin)
 {
  switch (pin) {
 #if CONFIG_IDF_TARGET_ESP32C3
  case 0: case 1: case 2: case 3: case 4:
    return ADC_UNIT_1;
  case 5:
    return ADC_UNIT_2;
 #elif CONFIG_IDF_TARGET_ESP32
  case 32: case 33: case 34: case 35: case 36: case 39:
    return ADC_UNIT_1;
  case 0: case 2: case 4: case 12: case 13: case 14: case 15:
  case 25: case 26: case 27:
    return ADC_UNIT_2;
 #elif (CONFIG_IDF_TARGET_ESP32S3 || CONFIG_IDF_TARGET_ESP32S2)
  case 1: case 2: case 3: case 4: case 5:
  case 6: case 7: case 8: case 9: case 10:
    return ADC_UNIT_1;
  case 11: case 12: case 13: case 14: case 15:
  case 16: case 17: case 18: case 19: case 20:
    return ADC_UNIT_2;
 #endif
  }
  return -1;
 }
 static adc_channel_t
 pin_to_channel(uint8_t pin)
 {
  switch (pin) {
 #if CONFIG_IDF_TARGET_ESP32C3
  case 0: return ADC_CHANNEL_0;
  case 1: return ADC_CHANNEL_1;
  case 2: return ADC_CHANNEL_2;
  case 3: return ADC_CHANNEL_3;
  case 4: return ADC_CHANNEL_4;
  case 5: return ADC_CHANNEL_0;
 #elif CONFIG_IDF_TARGET_ESP32
  case 36: return ADC_CHANNEL_0;
  case 39: return ADC_CHANNEL_3;
  case 32: return ADC_CHANNEL_4;
  case 33: return ADC_CHANNEL_5;
  case 34: return ADC_CHANNEL_6;
  case 35: return ADC_CHANNEL_7;
  case 4:  return ADC_CHANNEL_0;
  case 0:  return ADC_CHANNEL_1;
  case 2:  return ADC_CHANNEL_2;
  case 15: return ADC_CHANNEL_3;
  case 13: return ADC_CHANNEL_4;
  case 12: return ADC_CHANNEL_5;
  case 14: return ADC_CHANNEL_6;
  case 27: return ADC_CHANNEL_7;
  case 25: return ADC_CHANNEL_8;
  case 26: return ADC_CHANNEL_9;
 #elif (CONFIG_IDF_TARGET_ESP32S3 || CONFIG_IDF_TARGET_ESP32S2)
  case 1:  return ADC_CHANNEL_0;
  case 2:  return ADC_CHANNEL_1;
  case 3:  return ADC_CHANNEL_2;
  case 4:  return ADC_CHANNEL_3;
  case 5:  return ADC_CHANNEL_4;
  case 6:  return ADC_CHANNEL_5;
  case 7:  return ADC_CHANNEL_6;
  case 8:  return ADC_CHANNEL_7;
  case 9:  return ADC_CHANNEL_8;
  case 10: return ADC_CHANNEL_9;
  case 11: return ADC_CHANNEL_0;
  case 12: return ADC_CHANNEL_1;
  case 13: return ADC_CHANNEL_2;
  case 14: return ADC_CHANNEL_3;
  case 15: return ADC_CHANNEL_4;
  case 16: return ADC_CHANNEL_5;
  case 17: return ADC_CHANNEL_6;
  case 18: return ADC_CHANNEL_7;
  case 19: return ADC_CHANNEL_8;
  case 20: return ADC_CHANNEL_9;
 #endif
  }
  return -1;
 }
 static int
 init_units(void)
 {
  adc_unit_t units[] = { ADC_UNIT_1, ADC_UNIT_2 };
  for (int i = 0; i < UNIT_NUM; i++) {
    adc_oneshot_unit_init_cfg_t cfg = {
      .unit_id = units[i],
      .ulp_mode = ADC_ULP_MODE_DISABLE,
    };
    if (adc_oneshot_new_unit(&cfg, &adc_handles[i]) != ESP_OK)
      return -1;
  }
  return 0;
 }
 int
 mrb_adc_init(uint8_t pin)
 {
  if (!adc_initialized) {
    if (init_units() != 0) return -1;
    adc_initialized = true;
  }
  int ch = pin_to_channel(pin);
  if (ch < 0) return -1;
  adc_unit_t unit = pin_to_unit(pin);
  if (unit < 0 || unit >= UNIT_NUM) return -1;
  adc_oneshot_chan_cfg_t cfg = {
    .atten = ADC_ATTEN_DB_12,
    .bitwidth = ADC_BITWIDTH_DEFAULT,
  };
  if (adc_oneshot_config_channel(adc_handles[unit], ch, &cfg) != ESP_OK)
    return -1;
  return (int)pin;
 }
 uint32_t
 mrb_adc_read_raw(uint8_t input)
 {
  adc_unit_t unit = pin_to_unit(input);
  int ch = pin_to_channel(input);
  int raw = 0;
  if (unit >= 0 && unit < UNIT_NUM)
    adc_oneshot_read(adc_handles[unit], ch, &raw);
  return (uint32_t)raw;
 }
 float
 mrb_adc_read_voltage(uint8_t input)
 {
  return (float)mrb_adc_read_raw(input) * VOLTAGE_MAX / RESOLUTION;
 }
@@ -0,0 +1,43 @@
 #include <stdbool.h>
 #include "hardware/adc.h"
 #include <mruby/adc.h>
 #define VOLTAGE_MAX 3.3f
 #define RESOLUTION  4095
 #define TEMP_INPUT  4
 static bool adc_initialized;
 int
 mrb_adc_init(uint8_t pin)
 {
  if (!adc_initialized) {
    adc_init();
    adc_initialized = true;
  }
  uint input;
  switch (pin) {
  case 26: input = 0; break;
  case 27: input = 1; break;
  case 28: input = 2; break;
  case 29: input = 3; break;
  default: return -1;
  }
  adc_gpio_init(pin);
  return (int)input;
 }
 uint32_t
 mrb_adc_read_raw(uint8_t input)
 {
  adc_select_input(input);
  return (uint32_t)adc_read();
 }
 float
 mrb_adc_read_voltage(uint8_t input)
 {
  adc_select_input(input);
  return (float)adc_read() * VOLTAGE_MAX / RESOLUTION;
 }
@@ -0,0 +1,48 @@
 #include <mruby.h>
 #include <mruby/presym.h>
 #include <mruby/variable.h>
 #include <mruby/adc.h>
 /* ADC#__init(pin) */
 static mrb_value
 mrb_adc_m_init(mrb_state *mrb, mrb_value self)
 {
  mrb_int pin;
  mrb_get_args(mrb, "i", &pin);
  int input = mrb_adc_init((uint8_t)pin);
  if (input < 0) {
    mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid ADC pin");
  }
  return mrb_fixnum_value(input);
 }
 /* ADC#read_raw */
 static mrb_value
 mrb_adc_m_read_raw(mrb_state *mrb, mrb_value self)
 {
  mrb_int input = mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(input)));
  return mrb_fixnum_value(mrb_adc_read_raw((uint8_t)input));
 }
 /* ADC#read_voltage (also aliased as read) */
 static mrb_value
 mrb_adc_m_read_voltage(mrb_state *mrb, mrb_value self)
 {
  mrb_int input = mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(input)));
  return mrb_float_value(mrb, (mrb_float)mrb_adc_read_voltage((uint8_t)input));
 }
 void
 mrb_hw_adc_gem_init(mrb_state *mrb)
 {
  struct RClass *cls = mrb_define_class_id(mrb, MRB_SYM(ADC), mrb->object_class);
  mrb_define_method_id(mrb, cls, MRB_SYM(__init), mrb_adc_m_init, MRB_ARGS_REQ(1));
  mrb_define_method_id(mrb, cls, MRB_SYM(read_raw), mrb_adc_m_read_raw, MRB_ARGS_NONE());
  mrb_define_method_id(mrb, cls, MRB_SYM(read_voltage), mrb_adc_m_read_voltage, MRB_ARGS_NONE());
  mrb_define_method_id(mrb, cls, MRB_SYM(read), mrb_adc_m_read_voltage, MRB_ARGS_NONE());
 }
 void
 mrb_hw_adc_gem_final(mrb_state *mrb)
 {
 }
@@ -0,0 +1,144 @@
 # hw-gpio - GPIO peripheral interface for mruby
 This gem provides the `GPIO` class for controlling general-purpose
 input/output pins from mruby.
 It is designed for embedded platforms such as ESP32 and RP2040.
 ## Architecture
 Platform-specific HAL implementations are in `ports/` directories:
 - `ports/esp32/` - ESP32 using ESP-IDF GPIO driver
 - `ports/rp2040/` - RP2040 using Pico SDK
 The build system automatically compiles matching port sources based
 on `conf.ports` setting.
 ## Build Configuration
 ```ruby
 # For ESP32
 MRuby::CrossBuild.new('esp32') do |conf|
  conf.ports :esp32
  conf.gem core: 'hw-gpio'
 end
 # For RP2040
 MRuby::CrossBuild.new('rp2040') do |conf|
  conf.ports :rp2040
  conf.gem core: 'hw-gpio'
 end
 ```
 ## Ruby API
 ### Constants (direction/mode flags)
 These flags can be combined with bitwise OR.
 | Flag               | Value  | Description                |
 | ------------------ | ------ | -------------------------- |
 | `GPIO::IN`         | `0x01` | Input mode                 |
 | `GPIO::OUT`        | `0x02` | Output mode                |
 | `GPIO::HIGH_Z`     | `0x04` | High-impedance (tri-state) |
 | `GPIO::PULL_UP`    | `0x08` | Enable pull-up resistor    |
 | `GPIO::PULL_DOWN`  | `0x10` | Enable pull-down resistor  |
 | `GPIO::OPEN_DRAIN` | `0x20` | Enable open-drain output   |
 ### GPIO.new
 ```ruby
 gpio = GPIO.new(pin, flags)
 ```
 - `pin` - GPIO pin number (Integer)
 - `flags` - direction and mode flags (combined with `|`)
 - Exactly one of `IN`, `OUT`, or `HIGH_Z` must be specified
 - `PULL_UP` and `PULL_DOWN` are mutually exclusive
 - Raises `ArgumentError` on invalid flag combinations
 ```ruby
 # Input with pull-up
 button = GPIO.new(2, GPIO::IN | GPIO::PULL_UP)
 # Output
 led = GPIO.new(25, GPIO::OUT)
 ```
 ### Instance Methods
 #### GPIO#read
 Read the current pin value.
 ```ruby
 val = gpio.read  # => 0 or 1
 ```
 #### GPIO#write
 Set the pin output value.
 ```ruby
 gpio.write(1)  # set high
 gpio.write(0)  # set low
 ```
 - Raises `ArgumentError` if value is not 0 or 1
 #### GPIO#high? / GPIO#low?
 ```ruby
 gpio.high?  # => true if read != 0
 gpio.low?   # => true if read == 0
 ```
 #### GPIO#pin
 ```ruby
 gpio.pin  # => pin number passed to new
 ```
 #### GPIO#setmode
 Reconfigure pin direction and mode flags after initialization.
 ```ruby
 gpio.setmode(GPIO::OUT)
 ```
 ### Class Methods
 These operate directly on pin numbers without creating an instance.
 ```ruby
 GPIO.read_at(pin)           # => 0 or 1
 GPIO.write_at(pin, val)     # set pin output (0 or 1)
 GPIO.set_dir_at(pin, flags) # set direction (IN/OUT/HIGH_Z)
 GPIO.pull_up_at(pin)        # enable pull-up
 GPIO.pull_down_at(pin)      # enable pull-down
 GPIO.open_drain_at(pin)     # enable open-drain
 ```
 ## HAL Interface
 To add support for a new platform, create a `ports/<name>/`
 directory and implement the following C functions declared in
 `<mruby/gpio.h>`:
 ```c
 void mrb_gpio_init(uint8_t pin);
 void mrb_gpio_set_dir(uint8_t pin, uint8_t flags);
 void mrb_gpio_pull_up(uint8_t pin);
 void mrb_gpio_pull_down(uint8_t pin);
 void mrb_gpio_open_drain(uint8_t pin);
 int  mrb_gpio_read(uint8_t pin);
 void mrb_gpio_write(uint8_t pin, uint8_t val);
 ```
 The port sources are compiled automatically when the build
 configuration includes a matching `conf.ports` tag.
 ## License
 MIT
@@ -0,0 +1,31 @@
 #ifndef MRUBY_GPIO_H
 #define MRUBY_GPIO_H
 #include <stdint.h>
 #ifdef __cplusplus
 extern "C" {
 #endif
 /* direction/mode flags (bitmask) */
 #define MRB_GPIO_IN         0x01
 #define MRB_GPIO_OUT        0x02
 #define MRB_GPIO_HIGH_Z     0x04
 #define MRB_GPIO_PULL_UP    0x08
 #define MRB_GPIO_PULL_DOWN  0x10
 #define MRB_GPIO_OPEN_DRAIN 0x20
 /* HAL functions - implemented by hw-<platform>-gpio gems */
 void mrb_gpio_init(uint8_t pin);
 void mrb_gpio_set_dir(uint8_t pin, uint8_t flags);
 void mrb_gpio_pull_up(uint8_t pin);
 void mrb_gpio_pull_down(uint8_t pin);
 void mrb_gpio_open_drain(uint8_t pin);
 int  mrb_gpio_read(uint8_t pin);
 void mrb_gpio_write(uint8_t pin, uint8_t val);
 #ifdef __cplusplus
 }
 #endif
 #endif /* MRUBY_GPIO_H */
@@ -0,0 +1,5 @@
 MRuby::Gem::Specification.new('hw-gpio') do |spec|
  spec.license = 'MIT'
  spec.authors = ['HASUMI Hitoshi', 'mruby developers']
  spec.summary = 'GPIO peripheral interface'
 end
@@ -0,0 +1,44 @@
 class GPIO
  IN         = 0x01
  OUT        = 0x02
  HIGH_Z     = 0x04
  PULL_UP    = 0x08
  PULL_DOWN  = 0x10
  OPEN_DRAIN = 0x20
  attr_reader :pin
  def initialize(pin, flags)
    @pin = pin
    __init(pin)
    setmode(flags)
  end
  def setmode(flags)
    dir = flags & (IN | OUT | HIGH_Z)
    n = (flags & IN != 0 ? 1 : 0) + (flags & OUT != 0 ? 1 : 0) + (flags & HIGH_Z != 0 ? 1 : 0)
    if n == 0
      raise ArgumentError, "specify one of IN, OUT, or HIGH_Z"
    elsif n > 1
      raise ArgumentError, "IN, OUT, and HIGH_Z are exclusive"
    end
    GPIO.set_dir_at(@pin, dir)
    pull = flags & (PULL_UP | PULL_DOWN)
    if pull == (PULL_UP | PULL_DOWN)
      raise ArgumentError, "PULL_UP and PULL_DOWN are exclusive"
    end
    GPIO.pull_up_at(@pin) if pull == PULL_UP
    GPIO.pull_down_at(@pin) if pull == PULL_DOWN
    GPIO.open_drain_at(@pin) if flags & OPEN_DRAIN != 0
    nil
  end
  def high?
    read != 0
  end
  def low?
    read == 0
  end
 end
@@ -0,0 +1,50 @@
 #include "driver/gpio.h"
 #include <mruby/gpio.h>
 void
 mrb_gpio_init(uint8_t pin)
 {
  gpio_reset_pin(pin);
 }
 void
 mrb_gpio_set_dir(uint8_t pin, uint8_t flags)
 {
  if (flags & MRB_GPIO_IN) {
    gpio_set_direction(pin, GPIO_MODE_INPUT);
  }
  else if (flags & MRB_GPIO_OUT) {
    gpio_set_direction(pin, GPIO_MODE_OUTPUT);
  }
  /* HIGH_Z: not yet implemented */
 }
 void
 mrb_gpio_pull_up(uint8_t pin)
 {
  gpio_pullup_en(pin);
 }
 void
 mrb_gpio_pull_down(uint8_t pin)
 {
  gpio_pulldown_en(pin);
 }
 void
 mrb_gpio_open_drain(uint8_t pin)
 {
  /* not yet implemented */
 }
 int
 mrb_gpio_read(uint8_t pin)
 {
  return gpio_get_level(pin);
 }
 void
 mrb_gpio_write(uint8_t pin, uint8_t val)
 {
  gpio_set_level(pin, val);
 }
@@ -0,0 +1,51 @@
 #include <stdbool.h>
 #include "hardware/gpio.h"
 #include <mruby/gpio.h>
 void
 mrb_gpio_init(uint8_t pin)
 {
  gpio_init(pin);
 }
 void
 mrb_gpio_set_dir(uint8_t pin, uint8_t flags)
 {
  if (flags & MRB_GPIO_IN) {
    gpio_set_dir(pin, false);
  }
  else if (flags & MRB_GPIO_OUT) {
    gpio_set_dir(pin, true);
  }
  /* HIGH_Z: not yet implemented */
 }
 void
 mrb_gpio_pull_up(uint8_t pin)
 {
  gpio_pull_up(pin);
 }
 void
 mrb_gpio_pull_down(uint8_t pin)
 {
  gpio_pull_down(pin);
 }
 void
 mrb_gpio_open_drain(uint8_t pin)
 {
  /* not yet implemented */
 }
 int
 mrb_gpio_read(uint8_t pin)
 {
  return gpio_get(pin);
 }
 void
 mrb_gpio_write(uint8_t pin, uint8_t val)
 {
  gpio_put(pin, val == 1);
 }
@@ -0,0 +1,119 @@
 #include <mruby.h>
 #include <mruby/presym.h>
 #include <mruby/variable.h>
 #include <mruby/gpio.h>
 static mrb_value
 mrb_gpio_m_init(mrb_state *mrb, mrb_value self)
 {
  mrb_int pin;
  mrb_get_args(mrb, "i", &pin);
  mrb_gpio_init((uint8_t)pin);
  return mrb_nil_value();
 }
 /* GPIO.set_dir_at(pin, flags) */
 static mrb_value
 mrb_gpio_s_set_dir_at(mrb_state *mrb, mrb_value klass)
 {
  mrb_int pin, flags;
  mrb_get_args(mrb, "ii", &pin, &flags);
  mrb_gpio_set_dir((uint8_t)pin, (uint8_t)flags);
  return mrb_nil_value();
 }
 /* GPIO.pull_up_at(pin) */
 static mrb_value
 mrb_gpio_s_pull_up_at(mrb_state *mrb, mrb_value klass)
 {
  mrb_int pin;
  mrb_get_args(mrb, "i", &pin);
  mrb_gpio_pull_up((uint8_t)pin);
  return mrb_nil_value();
 }
 /* GPIO.pull_down_at(pin) */
 static mrb_value
 mrb_gpio_s_pull_down_at(mrb_state *mrb, mrb_value klass)
 {
  mrb_int pin;
  mrb_get_args(mrb, "i", &pin);
  mrb_gpio_pull_down((uint8_t)pin);
  return mrb_nil_value();
 }
 /* GPIO.open_drain_at(pin) */
 static mrb_value
 mrb_gpio_s_open_drain_at(mrb_state *mrb, mrb_value klass)
 {
  mrb_int pin;
  mrb_get_args(mrb, "i", &pin);
  mrb_gpio_open_drain((uint8_t)pin);
  return mrb_nil_value();
 }
 /* GPIO.read_at(pin) */
 static mrb_value
 mrb_gpio_s_read_at(mrb_state *mrb, mrb_value klass)
 {
  mrb_int pin;
  mrb_get_args(mrb, "i", &pin);
  return mrb_fixnum_value(mrb_gpio_read((uint8_t)pin));
 }
 /* GPIO.write_at(pin, val) */
 static mrb_value
 mrb_gpio_s_write_at(mrb_state *mrb, mrb_value klass)
 {
  mrb_int pin, val;
  mrb_get_args(mrb, "ii", &pin, &val);
  if (val != 0 && val != 1) {
    mrb_raise(mrb, E_ARGUMENT_ERROR, "value must be 0 or 1");
  }
  mrb_gpio_write((uint8_t)pin, (uint8_t)val);
  return mrb_nil_value();
 }
 /* GPIO#read */
 static mrb_value
 mrb_gpio_m_read(mrb_state *mrb, mrb_value self)
 {
  mrb_int pin = mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(pin)));
  return mrb_fixnum_value(mrb_gpio_read((uint8_t)pin));
 }
 /* GPIO#write(val) */
 static mrb_value
 mrb_gpio_m_write(mrb_state *mrb, mrb_value self)
 {
  mrb_int val;
  mrb_get_args(mrb, "i", &val);
  if (val != 0 && val != 1) {
    mrb_raise(mrb, E_ARGUMENT_ERROR, "value must be 0 or 1");
  }
  mrb_int pin = mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(pin)));
  mrb_gpio_write((uint8_t)pin, (uint8_t)val);
  return mrb_nil_value();
 }
 void
 mrb_hw_gpio_gem_init(mrb_state *mrb)
 {
  struct RClass *cls = mrb_define_class_id(mrb, MRB_SYM(GPIO), mrb->object_class);
  mrb_define_method_id(mrb, cls, MRB_SYM(__init), mrb_gpio_m_init, MRB_ARGS_REQ(1));
  mrb_define_method_id(mrb, cls, MRB_SYM(read), mrb_gpio_m_read, MRB_ARGS_NONE());
  mrb_define_method_id(mrb, cls, MRB_SYM(write), mrb_gpio_m_write, MRB_ARGS_REQ(1));
  mrb_define_class_method_id(mrb, cls, MRB_SYM(set_dir_at), mrb_gpio_s_set_dir_at, MRB_ARGS_REQ(2));
  mrb_define_class_method_id(mrb, cls, MRB_SYM(pull_up_at), mrb_gpio_s_pull_up_at, MRB_ARGS_REQ(1));
  mrb_define_class_method_id(mrb, cls, MRB_SYM(pull_down_at), mrb_gpio_s_pull_down_at, MRB_ARGS_REQ(1));
  mrb_define_class_method_id(mrb, cls, MRB_SYM(open_drain_at), mrb_gpio_s_open_drain_at, MRB_ARGS_REQ(1));
  mrb_define_class_method_id(mrb, cls, MRB_SYM(read_at), mrb_gpio_s_read_at, MRB_ARGS_REQ(1));
  mrb_define_class_method_id(mrb, cls, MRB_SYM(write_at), mrb_gpio_s_write_at, MRB_ARGS_REQ(2));
 }
 void
 mrb_hw_gpio_gem_final(mrb_state *mrb)
 {
 }
@@ -0,0 +1,162 @@
 # hw-i2c - I2C peripheral interface for mruby
 This gem provides the `I2C` class for communicating with I2C devices from mruby. It is designed for embedded platforms such as ESP32 and RP2040.
 ## Architecture
 Platform-specific HAL implementations are in `ports/` directories:
 - `ports/esp32/` - ESP32 using ESP-IDF I2C master driver
 - `ports/rp2040/` - RP2040 using Pico SDK
 The build system automatically compiles matching port sources based
 on `conf.ports` setting.
 ## Build Configuration
 ```ruby
 # For ESP32
 MRuby::CrossBuild.new('esp32') do |conf|
  conf.ports :esp32
  conf.gem core: 'hw-i2c'
 end
 # For RP2040
 MRuby::CrossBuild.new('rp2040') do |conf|
  conf.ports :rp2040
  conf.gem core: 'hw-i2c'
 end
 ```
 ## Ruby API
 ### I2C.new
 ```ruby
 i2c = I2C.new(
  unit:      :ESP32_I2C0,   # I2C unit name (platform-specific, required)
  frequency: 100_000,       # bus frequency in Hz (default: 100kHz)
  sda_pin:   21,            # SDA GPIO pin number (default: -1 for platform default)
  scl_pin:   22,            # SCL GPIO pin number (default: -1 for platform default)
  timeout:   500            # default timeout in ms (default: 500)
 )
 ```
 #### Unit Names
 | Platform | Available Units                |
 | -------- | ------------------------------ |
 | ESP32    | `:ESP32_I2C0`, `:ESP32_I2C1`   |
 | RP2040   | `:RP2040_I2C0`, `:RP2040_I2C1` |
 On RP2040, if `sda_pin` or `scl_pin` is -1, the Pico SDK default pins are used.
 ### I2C#write
 Write data to an I2C device.
 ```ruby
 i2c.write(addr, *data, timeout: 500)
 ```
 - `addr` - 7-bit I2C device address (Integer)
 - `data` - one or more data arguments, each can be:
  - **Integer** - a single byte (0-255)
  - **Array of Integer** - multiple bytes
  - **String** - raw bytes
 - `timeout:` - optional timeout in ms (overrides instance default)
 - Returns the number of bytes written (Integer)
 - Raises `IOError` on failure
 ```ruby
 # Write a single byte
 i2c.write(0x3C, 0x00)
 # Write multiple bytes
 i2c.write(0x3C, 0x00, [0xAE, 0xD5, 0x80])
 # Write a string
 i2c.write(0x3C, "hello")
 # Mix data types
 i2c.write(0x3C, 0x40, [0x01, 0x02], "data")
 ```
 ### I2C#read
 Read data from an I2C device. Optionally write data before reading (repeated START).
 ```ruby
 i2c.read(addr, length, *write_data, timeout: 500)
 ```
 - `addr` - 7-bit I2C device address (Integer)
 - `length` - number of bytes to read (Integer, must be positive)
 - `write_data` - optional data to write before reading (same format as `write`). When provided, the gem performs a write-then-read transaction using I2C repeated START condition. This is the standard way to read from a specific register.
 - `timeout:` - optional timeout in ms (overrides instance default)
 - Returns the data read (String)
 - Raises `IOError` on failure, `ArgumentError` if length <= 0
 ```ruby
 # Simple read (2 bytes from device)
 data = i2c.read(0x50, 2)
 # Register read: write register address 0x00, then read 2 bytes
 data = i2c.read(0x50, 2, 0x00)
 # Multi-byte register address
 data = i2c.read(0x50, 4, [0x00, 0x10])
 ```
 ### I2C#scan
 Scan the I2C bus for responsive devices.
 ```ruby
 i2c.scan(timeout: 500)
 ```
 - `timeout:` - optional timeout per probe in ms
 - Returns an Array of 7-bit addresses (Integer) that responded
 ```ruby
 found = i2c.scan
 # => [0x3C, 0x50, 0x68]
 ```
 ## HAL Interface
 To add support for a new platform, create a `ports/<name>/`
 directory and implement the following C functions declared in
 `<mruby/i2c.h>`:
 ```c
 int mrb_i2c_unit_name_to_num(const char *name);
 mrb_i2c_status mrb_i2c_init(int unit, uint32_t freq, int8_t sda, int8_t scl);
 int mrb_i2c_read(int unit, uint8_t addr, uint8_t *dst, size_t len,
                 uint32_t timeout_us);
 int mrb_i2c_write(int unit, uint8_t addr, const uint8_t *src, size_t len,
                  uint32_t timeout_us);
 int mrb_i2c_write_read(int unit, uint8_t addr,
                       const uint8_t *src, size_t wlen,
                       uint8_t *dst, size_t rlen,
                       uint32_t timeout_us);
 ```
 The port sources are compiled automatically when the build
 configuration includes a matching `conf.ports` tag.
 ### Error Codes
 ```c
 typedef enum {
  MRB_I2C_OK             =  0,
  MRB_I2C_ERROR_UNIT     = -1,  /* invalid or uninitialized unit */
  MRB_I2C_ERROR_TIMEOUT  = -2,  /* communication timeout */
  MRB_I2C_ERROR_NACK     = -3,  /* device did not acknowledge */
 } mrb_i2c_status;
 ```
 ## License
 MIT
@@ -0,0 +1,31 @@
 #ifndef MRUBY_I2C_H
 #define MRUBY_I2C_H
 #include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
 #ifdef __cplusplus
 extern "C" {
 #endif
 typedef enum {
  MRB_I2C_OK             =  0,
  MRB_I2C_ERROR_UNIT     = -1,
  MRB_I2C_ERROR_TIMEOUT  = -2,
  MRB_I2C_ERROR_NACK     = -3,
 } mrb_i2c_status;
 /* HAL functions - implemented by hw-<platform>-i2c gems */
 mrb_i2c_status mrb_i2c_init(int unit, uint32_t freq, int8_t sda, int8_t scl);
 int mrb_i2c_read(int unit, uint8_t addr, uint8_t *dst, size_t len, uint32_t timeout_us);
 int mrb_i2c_write(int unit, uint8_t addr, const uint8_t *src, size_t len, uint32_t timeout_us);
 int mrb_i2c_write_read(int unit, uint8_t addr, const uint8_t *src, size_t wlen,
                       uint8_t *dst, size_t rlen, uint32_t timeout_us);
 int mrb_i2c_unit_name_to_num(const char *name);
 #ifdef __cplusplus
 }
 #endif
 #endif /* MRUBY_I2C_H */
@@ -0,0 +1,5 @@
 MRuby::Gem::Specification.new('hw-i2c') do |spec|
  spec.license = 'MIT'
  spec.authors = ['HASUMI Hitoshi', 'mruby developers']
  spec.summary = 'I2C peripheral interface'
 end
@@ -0,0 +1,21 @@
 class I2C
  DEFAULT_FREQUENCY = 100_000 # Hz
  DEFAULT_TIMEOUT = 500 # ms
  def initialize(unit:, frequency: DEFAULT_FREQUENCY, sda_pin: -1, scl_pin: -1, timeout: DEFAULT_TIMEOUT)
    @timeout = timeout
    @unit_num = __init(unit.to_s, frequency, sda_pin, scl_pin)
  end
  def scan(timeout: @timeout)
    found = []
    (0x08..0x77).each do |addr|
      begin
        read(addr, 1, timeout: timeout)
        found << addr
      rescue IOError
      end
    end
    found
  end
 end
@@ -0,0 +1,117 @@
 #include <string.h>
 #include "driver/i2c_master.h"
 #include <mruby/i2c.h>
 typedef struct {
  i2c_master_bus_handle_t bus;
  uint32_t freq;
  bool initialized;
 } i2c_ctx;
 /* ESP32 supports up to 2 I2C ports */
 static i2c_ctx ctx[2];
 static bool
 valid_unit(int unit)
 {
  return unit >= 0 && unit <= 1 && ctx[unit].initialized;
 }
 static uint32_t
 us_to_ms(uint32_t timeout_us)
 {
  uint32_t ms = (timeout_us + 999) / 1000;
  return (ms < 10) ? 10 : ms;
 }
 static i2c_master_dev_handle_t
 add_device(int unit, uint8_t addr)
 {
  i2c_device_config_t cfg = {
    .dev_addr_length = I2C_ADDR_BIT_LEN_7,
    .device_address = addr,
    .scl_speed_hz = ctx[unit].freq,
  };
  i2c_master_dev_handle_t dev;
  if (i2c_master_bus_add_device(ctx[unit].bus, &cfg, &dev) != ESP_OK)
    return NULL;
  return dev;
 }
 int
 mrb_i2c_unit_name_to_num(const char *name)
 {
  if (strcmp(name, "ESP32_I2C0") == 0) return 0;
  if (strcmp(name, "ESP32_I2C1") == 0) return 1;
  return MRB_I2C_ERROR_UNIT;
 }
 mrb_i2c_status
 mrb_i2c_init(int unit, uint32_t freq, int8_t sda, int8_t scl)
 {
  if (unit < 0 || unit > 1) return MRB_I2C_ERROR_UNIT;
  if (ctx[unit].initialized) {
    i2c_del_master_bus(ctx[unit].bus);
    ctx[unit].initialized = false;
  }
  i2c_master_bus_config_t cfg = {
    .clk_source = I2C_CLK_SRC_DEFAULT,
    .i2c_port = unit,
    .scl_io_num = scl,
    .sda_io_num = sda,
    .glitch_ignore_cnt = 7,
    .flags.enable_internal_pullup = true,
  };
  esp_err_t err = i2c_new_master_bus(&cfg, &ctx[unit].bus);
  if (err != ESP_OK) return MRB_I2C_ERROR_UNIT;
  ctx[unit].initialized = true;
  ctx[unit].freq = freq;
  return MRB_I2C_OK;
 }
 int
 mrb_i2c_read(int unit, uint8_t addr, uint8_t *dst, size_t len,
             uint32_t timeout_us)
 {
  if (!valid_unit(unit)) return MRB_I2C_ERROR_UNIT;
  i2c_master_dev_handle_t dev = add_device(unit, addr);
  if (!dev) return -1;
  esp_err_t err = i2c_master_receive(dev, dst, len, us_to_ms(timeout_us));
  i2c_master_bus_rm_device(dev);
  return (err == ESP_OK) ? (int)len : -1;
 }
 int
 mrb_i2c_write(int unit, uint8_t addr, const uint8_t *src, size_t len,
              uint32_t timeout_us)
 {
  if (!valid_unit(unit)) return MRB_I2C_ERROR_UNIT;
  i2c_master_dev_handle_t dev = add_device(unit, addr);
  if (!dev) return -1;
  esp_err_t err = i2c_master_transmit(dev, src, len, us_to_ms(timeout_us));
  i2c_master_bus_rm_device(dev);
  return (err == ESP_OK) ? (int)len : -1;
 }
 int
 mrb_i2c_write_read(int unit, uint8_t addr, const uint8_t *src, size_t wlen,
                   uint8_t *dst, size_t rlen, uint32_t timeout_us)
 {
  if (!valid_unit(unit)) return MRB_I2C_ERROR_UNIT;
  i2c_master_dev_handle_t dev = add_device(unit, addr);
  if (!dev) return -1;
  esp_err_t err = i2c_master_transmit_receive(dev, src, wlen, dst, rlen,
                                               us_to_ms(timeout_us));
  i2c_master_bus_rm_device(dev);
  return (err == ESP_OK) ? (int)rlen : -1;
 }
@@ -0,0 +1,64 @@
 #include <string.h>
 #include "pico/stdlib.h"
 #include "hardware/i2c.h"
 #include <mruby/i2c.h>
 #define UNIT_SELECT(u) \
  i2c_inst_t *inst; \
  switch (u) { \
  case 0: inst = i2c0; break; \
  case 1: inst = i2c1; break; \
  default: return MRB_I2C_ERROR_UNIT; \
  }
 int
 mrb_i2c_unit_name_to_num(const char *name)
 {
  if (strcmp(name, "RP2040_I2C0") == 0) return 0;
  if (strcmp(name, "RP2040_I2C1") == 0) return 1;
  return MRB_I2C_ERROR_UNIT;
 }
 mrb_i2c_status
 mrb_i2c_init(int unit, uint32_t freq, int8_t sda, int8_t scl)
 {
  UNIT_SELECT(unit);
  i2c_init(inst, freq);
  if (sda < 0) sda = PICO_DEFAULT_I2C_SDA_PIN;
  if (scl < 0) scl = PICO_DEFAULT_I2C_SCL_PIN;
  gpio_set_function(sda, GPIO_FUNC_I2C);
  gpio_set_function(scl, GPIO_FUNC_I2C);
  gpio_pull_up(sda);
  gpio_pull_up(scl);
  return MRB_I2C_OK;
 }
 int
 mrb_i2c_read(int unit, uint8_t addr, uint8_t *dst, size_t len,
             uint32_t timeout_us)
 {
  UNIT_SELECT(unit);
  return i2c_read_timeout_us(inst, addr, dst, len, false, timeout_us);
 }
 int
 mrb_i2c_write(int unit, uint8_t addr, const uint8_t *src, size_t len,
              uint32_t timeout_us)
 {
  UNIT_SELECT(unit);
  return i2c_write_timeout_us(inst, addr, src, len, false, timeout_us);
 }
 int
 mrb_i2c_write_read(int unit, uint8_t addr, const uint8_t *src, size_t wlen,
                   uint8_t *dst, size_t rlen, uint32_t timeout_us)
 {
  UNIT_SELECT(unit);
  /* write with nostop=true (no STOP, keeps bus for repeated START) */
  int ret = i2c_write_timeout_us(inst, addr, src, wlen, true, timeout_us);
  if (ret < 0) return ret;
  /* read with nostop=false (STOP after read) */
  return i2c_read_timeout_us(inst, addr, dst, rlen, false, timeout_us);
 }
@@ -0,0 +1,200 @@
 #include <string.h>
 #include <mruby.h>
 #include <mruby/presym.h>
 #include <mruby/variable.h>
 #include <mruby/array.h>
 #include <mruby/string.h>
 #include <mruby/i2c.h>
 #define STACK_BUF_SIZE 256
 #define E_IO_ERROR mrb_exc_get_id(mrb, MRB_SYM(IOError))
 static size_t
 i2c_fill_buf(mrb_state *mrb, uint8_t *buf, mrb_value *args, mrb_int argc)
 {
  size_t pos = 0;
  for (mrb_int i = 0; i < argc; i++) {
    switch (mrb_type(args[i])) {
    case MRB_TT_ARRAY: {
      mrb_int alen = RARRAY_LEN(args[i]);
      const mrb_value *aptr = RARRAY_PTR(args[i]);
      for (mrb_int j = 0; j < alen; j++) {
        if (!mrb_integer_p(aptr[j])) {
          mrb_raise(mrb, E_TYPE_ERROR, "array element must be Integer");
        }
        buf[pos++] = (uint8_t)mrb_integer(aptr[j]);
      }
      break;
    }
    case MRB_TT_INTEGER:
      buf[pos++] = (uint8_t)mrb_integer(args[i]);
      break;
    case MRB_TT_STRING:
      memcpy(&buf[pos], RSTRING_PTR(args[i]), RSTRING_LEN(args[i]));
      pos += RSTRING_LEN(args[i]);
      break;
    default:
      break;
    }
  }
  return pos;
 }
 static size_t
 i2c_calc_size(mrb_state *mrb, mrb_value *args, mrb_int argc)
 {
  size_t total = 0;
  for (mrb_int i = 0; i < argc; i++) {
    switch (mrb_type(args[i])) {
    case MRB_TT_ARRAY:
      total += RARRAY_LEN(args[i]);
      break;
    case MRB_TT_INTEGER:
      total += 1;
      break;
    case MRB_TT_STRING:
      total += RSTRING_LEN(args[i]);
      break;
    default:
      mrb_raise(mrb, E_TYPE_ERROR, "Integer, Array, or String expected");
    }
  }
  return total;
 }
 /* Allocate write buffer, fill it, return pointer and size.
   Caller must free if need_free is set. */
 static uint8_t*
 i2c_build_buf(mrb_state *mrb, mrb_value *args, mrb_int argc,
              size_t *out_len, uint8_t *sbuf, mrb_bool *need_free)
 {
  size_t total = i2c_calc_size(mrb, args, argc);
  uint8_t *buf;
  if (total <= STACK_BUF_SIZE) {
    buf = sbuf;
    *need_free = FALSE;
  }
  else {
    buf = (uint8_t*)mrb_malloc(mrb, total);
    *need_free = TRUE;
  }
  i2c_fill_buf(mrb, buf, args, argc);
  *out_len = total;
  return buf;
 }
 static mrb_int
 get_timeout(mrb_state *mrb, mrb_value self, mrb_value kw)
 {
  if (mrb_undef_p(kw)) {
    return mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(timeout)));
  }
  return mrb_integer(kw);
 }
 static mrb_value
 mrb_i2c_m_write(mrb_state *mrb, mrb_value self)
 {
  mrb_value *args;
  mrb_int argc, addr;
  const mrb_sym kw_names[] = { MRB_SYM(timeout) };
  mrb_value kw_values[1];
  mrb_kwargs kwargs = { 1, 0, kw_names, kw_values, NULL };
  mrb_get_args(mrb, "i*:", &addr, &args, &argc, &kwargs);
  mrb_int timeout_ms = get_timeout(mrb, self, kw_values[0]);
  mrb_int unit = mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(unit_num)));
  uint8_t sbuf[STACK_BUF_SIZE];
  size_t wlen;
  mrb_bool need_free;
  uint8_t *buf = i2c_build_buf(mrb, args, argc, &wlen, sbuf, &need_free);
  int ret = mrb_i2c_write((int)unit, (uint8_t)addr, buf, wlen,
                           (uint32_t)timeout_ms * 1000);
  if (need_free) mrb_free(mrb, buf);
  if (ret < 0) {
    mrb_raise(mrb, E_IO_ERROR, "I2C write failed");
  }
  return mrb_fixnum_value(ret);
 }
 static mrb_value
 mrb_i2c_m_read(mrb_state *mrb, mrb_value self)
 {
  mrb_value *args;
  mrb_int argc, addr, len;
  const mrb_sym kw_names[] = { MRB_SYM(timeout) };
  mrb_value kw_values[1];
  mrb_kwargs kwargs = { 1, 0, kw_names, kw_values, NULL };
  mrb_get_args(mrb, "ii*:", &addr, &len, &args, &argc, &kwargs);
  if (len <= 0) {
    mrb_raise(mrb, E_ARGUMENT_ERROR, "read length must be positive");
  }
  mrb_int timeout_ms = get_timeout(mrb, self, kw_values[0]);
  mrb_int unit = mrb_integer(mrb_iv_get(mrb, self, MRB_IVSYM(unit_num)));
  uint32_t timeout_us = (uint32_t)timeout_ms * 1000;
  uint8_t *rxbuf = (uint8_t*)mrb_malloc(mrb, len);
  int ret;
  if (argc > 0) {
    /* write-then-read (repeated START) */
    uint8_t sbuf[STACK_BUF_SIZE];
    size_t wlen;
    mrb_bool need_free;
    uint8_t *wbuf = i2c_build_buf(mrb, args, argc, &wlen, sbuf, &need_free);
    ret = mrb_i2c_write_read((int)unit, (uint8_t)addr,
                              wbuf, wlen, rxbuf, (size_t)len, timeout_us);
    if (need_free) mrb_free(mrb, wbuf);
  }
  else {
    ret = mrb_i2c_read((int)unit, (uint8_t)addr, rxbuf, (size_t)len, timeout_us);
  }
  if (ret < 0) {
    mrb_free(mrb, rxbuf);
    mrb_raise(mrb, E_IO_ERROR, "I2C read failed");
  }
  mrb_value str = mrb_str_new(mrb, (const char*)rxbuf, ret);
  mrb_free(mrb, rxbuf);
  return str;
 }
 static mrb_value
 mrb_i2c_m_init(mrb_state *mrb, mrb_value self)
 {
  const char *unit;
  mrb_int freq, sda, scl;
  mrb_get_args(mrb, "ziii", &unit, &freq, &sda, &scl);
  int num = mrb_i2c_unit_name_to_num(unit);
  if (num < 0) {
    mrb_raisef(mrb, E_ARGUMENT_ERROR, "unknown I2C unit: %s", unit);
  }
  mrb_i2c_status st = mrb_i2c_init(num, (uint32_t)freq, (int8_t)sda, (int8_t)scl);
  if (st != MRB_I2C_OK) {
    mrb_raise(mrb, E_IO_ERROR, "I2C init failed");
  }
  return mrb_fixnum_value(num);
 }
 void
 mrb_hw_i2c_gem_init(mrb_state *mrb)
 {
  struct RClass *cls = mrb_define_class_id(mrb, MRB_SYM(I2C), mrb->object_class);
  mrb_define_method_id(mrb, cls, MRB_SYM(__init), mrb_i2c_m_init, MRB_ARGS_REQ(4));
  mrb_define_method_id(mrb, cls, MRB_SYM(write), mrb_i2c_m_write, MRB_ARGS_REQ(1)|MRB_ARGS_REST()|MRB_ARGS_KEY(1, 0));
  mrb_define_method_id(mrb, cls, MRB_SYM(read), mrb_i2c_m_read, MRB_ARGS_REQ(2)|MRB_ARGS_REST()|MRB_ARGS_KEY(1, 0));
 }
 void
 mrb_hw_i2c_gem_final(mrb_state *mrb)
 {
 }
@@ -0,0 +1,87 @@
 # hw-pwm - PWM peripheral interface for mruby
 This gem provides the `PWM` class for Pulse Width Modulation
 output from mruby. It is designed for embedded platforms such as
 ESP32 and RP2040.
 ## Architecture
 Platform-specific HAL implementations are in `ports/` directories:
 - `ports/esp32/` - ESP32 using LEDC peripheral
 - `ports/rp2040/` - RP2040 using Pico SDK PWM hardware
 ## Build Configuration
 ```ruby
 MRuby::CrossBuild.new('esp32') do |conf|
  conf.ports :esp32
  conf.gem core: 'hw-pwm'
 end
 ```
 ## Ruby API
 ### PWM.new
 ```ruby
 pwm = PWM.new(pin, frequency: 1000, duty: 50)
 ```
 - `pin` - GPIO pin number (Integer)
 - `frequency:` - frequency in Hz (default: 0, disabled)
 - `duty:` - duty cycle in percent 0-100 (default: 50)
 ### PWM#frequency(freq)
 Set frequency in Hz. Returns the frequency. Setting 0 disables
 output.
 ```ruby
 pwm.frequency(1000)   # 1 kHz
 pwm.frequency(0)      # disable
 ```
 ### PWM#period_us(us)
 Set period in microseconds. Returns the corresponding frequency.
 ```ruby
 pwm.period_us(1000)   # 1ms period = 1 kHz
 ```
 ### PWM#duty(pct)
 Set duty cycle in percent (0.0-100.0). Clamped to range.
 ```ruby
 pwm.duty(75.0)
 ```
 ### PWM#pulse_width_us(us)
 Set pulse width in microseconds. Duty cycle is calculated from
 current frequency.
 ```ruby
 pwm.pulse_width_us(500)   # 500us pulse width
 ```
 ## HAL Interface
 To add support for a new platform, create a `ports/<name>/`
 directory and implement the following C functions declared in
 `<mruby/pwm.h>`:
 ```c
 void mrb_pwm_init(uint32_t pin);
 void mrb_pwm_set_freq_duty(uint32_t pin, float frequency, float duty);
 void mrb_pwm_set_enabled(uint32_t pin, bool enabled);
 ```
 - `frequency` is in Hz, `duty` is in percent (0-100)
 - `mrb_pwm_set_enabled` is called with `false` when frequency is 0
 ## License
 MIT
@@ -0,0 +1,20 @@
 #ifndef MRUBY_PWM_H
 #define MRUBY_PWM_H
 #include <stdint.h>
 #include <stdbool.h>
 #ifdef __cplusplus
 extern "C" {
 #endif
 /* HAL functions - implemented in ports/<platform>/pwm.c */
 void mrb_pwm_init(uint32_t pin);
 void mrb_pwm_set_freq_duty(uint32_t pin, float frequency, float duty);
 void mrb_pwm_set_enabled(uint32_t pin, bool enabled);
 #ifdef __cplusplus
 }
 #endif
 #endif /* MRUBY_PWM_H */
@@ -0,0 +1,5 @@
 MRuby::Gem::Specification.new('hw-pwm') do |spec|
  spec.license = 'MIT'
  spec.authors = ['HASUMI Hitoshi', 'mruby developers']
  spec.summary = 'PWM peripheral interface'
 end
@@ -0,0 +1,9 @@
 class PWM
  def initialize(pin, frequency: 0, duty: 50)
    @pin = pin
    __init(@pin)
    @frequency = frequency.to_f
    @duty = duty.to_f
    frequency(@frequency)
  end
 end
--- a/Show More
+++ b/Show More