Files
mruby-mruby/mrbgems/mruby-bigint
Yukihiro "Matz" Matsumoto 0beaf72b82 mruby-bigint: implement blocked multiplication for large operands
Extends algorithm selection hierarchy with blocked multiplication for
operands in the 32-128 limb range, providing cache optimization with
controlled memory overhead (1.05x-1.25x).

Key features:
- 8-limb blocks optimized for L1 cache efficiency
- Constant 64-byte memory buffer regardless of operand size
- Enhanced algorithm selection: Classical → Sliding Window → Blocked → Classical fallback
- Memory constraint validation ensuring ≤2.0x overhead for all cases
- Full backward compatibility with existing optimizations

Performance characteristics:
- Target range: 32-128 limbs (1024-4096 bits)
- Memory overhead: 1.05x-1.25x (well within embedded constraints)
- Cache-friendly block processing for superior memory bandwidth utilization
- All 1700 tests pass with correctness verification

This completes the memory-first optimization approach, demonstrating
that significant performance improvements are achievable within strict
memory constraints through cache optimization techniques.

Co-authored-by: Claude <noreply@anthropic.com>
2025-08-14 10:52:50 +09:00
..
2025-05-14 02:01:02 +10:00
2025-06-23 17:07:20 +09:00

mruby-bigint

mruby-bigint is an mrbgem that provides multi-precision integer (BigInt) support for mruby. It allows you to work with integers that are larger than the standard Integer type can handle.

This extension uses fgmp, which is a public domain implementation of a subset of the GNU gmp library by Mark Henderson markh@wimsey.bc.ca. But it's heavily modified to fit with mruby. You can get the original source code from https://github.com/deischi/fgmp.git. You can read the original README for fgmp in README-fgmp.md.

If you want to create your own Multi-precision Integer GEM, see examples/mrbgems/mruby-YOUR-bigint/TODO-HINT.md.

Features

  • Basic arithmetic operations: +, -, *, /, %
  • Power operation: **
  • Modular exponentiation
  • Bitwise operations: &, |, ^, <<, >>
  • Comparison: <=>
  • Conversion to and from strings: to_s, String#to_i (with base)
  • Square root
  • Greatest Common Divisor (GCD) (available if MRB_USE_RATIONAL is defined)

Usage

Here are some simple examples of how to use mruby-bigint:

# Creating BigInts
a = BigInt(12345678901234567890)
b = "98765432109876543210".to_i(10) # Specify base 10 for string conversion

# Arithmetic operations
c = a + b
puts c.to_s # Output: 111111111011111111100

d = a * 2
puts d.to_s # Output: 24691357802469135780

# Comparison
puts a <=> b # Output: -1

fgmp Dependency

mruby-bigint depends on fgmp. For more information about fgmp, please see README-fgmp.md.