# 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_LOADL16` | `BS` | `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_LOADSYM16` | `BS` | `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_SENDV` | `BB` | `R(a) = call(R(a),Syms(b),*R(a+1))` | | `OP_SENDVB` | `BB` | `R(a) = call(R(a),Syms(b),*R(a+1),&R(a+2))` | | `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_SENDVK` | `BB` | `R(a) = call(R(a),Syms(b),*R(a+1),**(a+2),&R(a+3))` | | `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_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` | `B` | `ary_push(R(a),R(a+1))` | | `OP_ARYDUP` | `B` | `R(a) = ary_dup(R(a))` | | `OP_AREF` | `BBB` | `R(a) = R(b)[c]` | | `OP_ASET` | `BBB` | `R(a)[c] = R(b)` | | `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(Lit(b))` | | `OP_STRING16` | `BS` | `R(a) = str_dup(Lit(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` | `R(a) = 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(SEQ[b],OP_L_LAMBDA)` | | `OP_LAMBDA16` | `BS` | `R(a) = lambda(SEQ[b],OP_L_LAMBDA)` | | `OP_BLOCK` | `BB` | `R(a) = lambda(SEQ[b],OP_L_BLOCK)` | | `OP_BLOCK16` | `BS` | `R(a) = lambda(SEQ[b],OP_L_BLOCK)` | | `OP_METHOD` | `BB` | `R(a) = lambda(SEQ[b],OP_L_METHOD)` | | `OP_METHOD16` | `BS` | `R(a) = lambda(SEQ[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),SEQ[b])` | | `OP_EXEC16` | `BS` | `R(a) = blockexec(R(a),SEQ[b])` | | `OP_DEF` | `BB` | `R(a).newmethod(Syms(b),R(a+1))` | | `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, Lit(a))` | | `OP_STOP` | `-` | `stop VM` | |------------------|--------------|--------------------------------------------------------|