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mruby-mruby/doc/internal/opcode.md
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fn ⌃ ⌥ 273fcbc347 ops.h: update OP_ARYDUP instruction and rename to OP_ARYSPLAT.
Transforms the value of a splat inside a return statement (similar
to an array). For example, `return *nil` should return `nil.to_a`,
while `return *1` should return `[1]`
2022-10-29 19:54:34 -07:00

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# The new bytecode
We will reimplement the VM to use 8bit instruction code. By
bytecode, we mean real byte code. The whole purpose is
reducing the memory consumption of mruby VM.
# Instructions
Instructions are bytes. There can be 256 instructions. Currently, we
have 94 instructions. Instructions can take 0 to 3 operands.
## operands
The size of operands can be either 8bits, 16bits or 24bits.
In the table.1 below, the second field describes the size (and
sign) of operands.
- B: 8bit
- S: 16bit
- sS: signed 16bit
- W: 24bit
## table.1 Instruction Table
| Instruction Name | Operand type | Semantics |
|--------------------|----------------|------------------------------------------------------------|
| `OP_NOP` | `-` | `no operation` |
| `OP_MOVE` | `BB` | `R(a) = R(b)` |
| `OP_LOADL` | `BB` | `R(a) = Pool(b)` |
| `OP_LOADI` | `BB` | `R(a) = mrb_int(b)` |
| `OP_LOADINEG` | `BB` | `R(a) = mrb_int(-b)` |
| `OP_LOADI__1` | `B` | `R(a) = mrb_int(-1)` |
| `OP_LOADI_0` | `B` | `R(a) = mrb_int(0)` |
| `OP_LOADI_1` | `B` | `R(a) = mrb_int(1)` |
| `OP_LOADI_2` | `B` | `R(a) = mrb_int(2)` |
| `OP_LOADI_3` | `B` | `R(a) = mrb_int(3)` |
| `OP_LOADI_4` | `B` | `R(a) = mrb_int(4)` |
| `OP_LOADI_5` | `B` | `R(a) = mrb_int(5)` |
| `OP_LOADI_6` | `B` | `R(a) = mrb_int(6)` |
| `OP_LOADI_7` | `B` | `R(a) = mrb_int(7)` |
| `OP_LOADI16` | `BS` | `R(a) = mrb_int(b)` |
| `OP_LOADI32` | `BSS` | `R(a) = mrb_int((b<<16)+c)` |
| `OP_LOADSYM` | `BB` | `R(a) = Syms(b)` |
| `OP_LOADNIL` | `B` | `R(a) = nil` |
| `OP_LOADSELF` | `B` | `R(a) = self` |
| `OP_LOADT` | `B` | `R(a) = true` |
| `OP_LOADF` | `B` | `R(a) = false` |
| `OP_GETGV` | `BB` | `R(a) = getglobal(Syms(b))` |
| `OP_SETGV` | `BB` | `setglobal(Syms(b), R(a))` |
| `OP_GETSV` | `BB` | `R(a) = Special[Syms(b)]` |
| `OP_SETSV` | `BB` | `Special[Syms(b)] = R(a)` |
| `OP_GETIV` | `BB` | `R(a) = ivget(Syms(b))` |
| `OP_SETIV` | `BB` | `ivset(Syms(b),R(a))` |
| `OP_GETCV` | `BB` | `R(a) = cvget(Syms(b))` |
| `OP_SETCV` | `BB` | `cvset(Syms(b),R(a))` |
| `OP_GETCONST` | `BB` | `R(a) = constget(Syms(b))` |
| `OP_SETCONST` | `BB` | `constset(Syms(b),R(a))` |
| `OP_GETMCNST` | `BB` | `R(a) = R(a)::Syms(b)` |
| `OP_SETMCNST` | `BB` | `R(a+1)::Syms(b) = R(a)` |
| `OP_GETUPVAR` | `BBB` | `R(a) = uvget(b,c)` |
| `OP_SETUPVAR` | `BBB` | `uvset(b,c,R(a))` |
| `OP_JMP` | `S` | `pc+=a` |
| `OP_JMPIF` | `BS` | `if R(a) pc+=b` |
| `OP_JMPNOT` | `BS` | `if !R(a) pc+=b` |
| `OP_JMPNIL` | `BS` | `if R(a)==nil pc+=b` |
| `OP_JMPUW` | `S` | `unwind_and_jump_to(a)` |
| `OP_EXCEPT` | `B` | `R(a) = exc` |
| `OP_RESCUE` | `BB` | `R(b) = R(a).isa?(R(b))` |
| `OP_RAISEIF` | `B` | `raise(R(a)) if R(a)` |
| `OP_SEND` | `BBB` | `R(a) = call(R(a),Syms(b),R(a+1),...,R(a+c))` |
| `OP_SENDB` | `BBB` | `R(a) = call(R(a),Syms(b),R(a+1),...,R(a+c),&R(a+c+1))` |
| `OP_CALL` | `-` | `R(0) = self.call(frame.argc, frame.argv)` |
| `OP_SUPER` | `BB` | `R(a) = super(R(a+1),... ,R(a+b+1))` |
| `OP_ARGARY` | `BS` | `R(a) = argument array (16=m5:r1:m5:d1:lv4)` |
| `OP_ENTER` | `W` | `arg setup according to flags (23=m5:o5:r1:m5:k5:d1:b1)` |
| `OP_KEY_P` | `BB` | `R(a) = kdict.key?(Syms(b))` |
| `OP_KEYEND` | `-` | `raise unless kdict.empty?` |
| `OP_KARG` | `BB` | `R(a) = kdict[Syms(b)]; kdict.delete(Syms(b))` |
| `OP_RETURN` | `B` | `return R(a) (normal)` |
| `OP_RETURN_BLK` | `B` | `return R(a) (in-block return)` |
| `OP_BREAK` | `B` | `break R(a)` |
| `OP_BLKPUSH` | `BS` | `R(a) = block (16=m5:r1:m5:d1:lv4)` |
| `OP_ADD` | `B` | `R(a) = R(a)+R(a+1)` |
| `OP_ADDI` | `BB` | `R(a) = R(a)+mrb_int(b)` |
| `OP_SUB` | `B` | `R(a) = R(a)-R(a+1)` |
| `OP_SUBI` | `BB` | `R(a) = R(a)-mrb_int(b)` |
| `OP_MUL` | `B` | `R(a) = R(a)*R(a+1)` |
| `OP_DIV` | `B` | `R(a) = R(a)/R(a+1)` |
| `OP_EQ` | `B` | `R(a) = R(a)==R(a+1)` |
| `OP_LT` | `B` | `R(a) = R(a)<R(a+1)` |
| `OP_LE` | `B` | `R(a) = R(a)<=R(a+1)` |
| `OP_GT` | `B` | `R(a) = R(a)>R(a+1)` |
| `OP_GE` | `B` | `R(a) = R(a)>=R(a+1)` |
| `OP_ARRAY` | `BB` | `R(a) = ary_new(R(a),R(a+1)..R(a+b))` |
| `OP_ARRAY2` | `BBB` | `R(a) = ary_new(R(b),R(b+1)..R(b+c))` |
| `OP_ARYCAT` | `B` | `ary_cat(R(a),R(a+1))` |
| `OP_ARYPUSH` | `BB` | `ary_push(R(a),R(a+1)..R(a+b))` |
| `OP_ARYSPLAT` | `B` | `R(a) = ary_splat(R(a))` |
| `OP_AREF` | `BBB` | `R(a) = R(b)[c]` |
| `OP_ASET` | `BBB` | `R(b)[c] = R(a)` |
| `OP_APOST` | `BBB` | `*R(a),R(a+1)..R(a+c) = R(a)[b..]` |
| `OP_INTERN` | `B` | `R(a) = intern(R(a))` |
| `OP_STRING` | `BB` | `R(a) = str_dup(Pool(b))` |
| `OP_STRCAT` | `B` | `str_cat(R(a),R(a+1))` |
| `OP_HASH` | `BB` | `R(a) = hash_new(R(a),R(a+1)..R(a+b*2-1))` |
| `OP_HASHADD` | `BB` | `hash_push(R(a),R(a+1)..R(a+b*2))` |
| `OP_HASHCAT` | `B` | `R(a) = hash_cat(R(a),R(a+1))` |
| `OP_LAMBDA` | `BB` | `R(a) = lambda(Irep(b),OP_L_LAMBDA)` |
| `OP_BLOCK` | `BB` | `R(a) = lambda(Irep(b),OP_L_BLOCK)` |
| `OP_METHOD` | `BB` | `R(a) = lambda(Irep(b),OP_L_METHOD)` |
| `OP_RANGE_INC` | `B` | `R(a) = range_new(R(a),R(a+1),FALSE)` |
| `OP_RANGE_EXC` | `B` | `R(a) = range_new(R(a),R(a+1),TRUE)` |
| `OP_OCLASS` | `B` | `R(a) = ::Object` |
| `OP_CLASS` | `BB` | `R(a) = newclass(R(a),Syms(b),R(a+1))` |
| `OP_MODULE` | `BB` | `R(a) = newmodule(R(a),Syms(b))` |
| `OP_EXEC` | `BB` | `R(a) = blockexec(R(a),Irep[b])` |
| `OP_DEF` | `BB` | `R(a).newmethod(Syms(b),R(a+1)); R(a) = Syms(b)` |
| `OP_ALIAS` | `BB` | `alias_method(target_class,Syms(a),Syms(b))` |
| `OP_UNDEF` | `B` | `undef_method(target_class,Syms(a))` |
| `OP_SCLASS` | `B` | `R(a) = R(a).singleton_class` |
| `OP_TCLASS` | `B` | `R(a) = target_class` |
| `OP_DEBUG` | `BBB` | `print a,b,c` |
| `OP_ERR` | `B` | `raise(LocalJumpError, Pool(a))` |
| `OP_EXT1` | `-` | `make 1st operand 16bit` |
| `OP_EXT2` | `-` | `make 2nd operand 16bit` |
| `OP_EXT3` | `-` | `make 1st and 2nd operands 16bit` |
| `OP_STOP` | `-` | `stop VM` |
| ------------------ | -------------- | ---------------------------------------------------------- |