Java教程
Lua虚拟机之字节码
本文主要是介绍Lua虚拟机之字节码，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！
Lua5.2官方手册 http://www.lua.org/manual/5.2/
Lua的字节码在意义上等价于cpu的指令码
字节码对照表。
package lua
import (
"fmt"
)
/*
gopherlua uses Lua 5.1.4's opcodes.
Lua 5.1.4 opcodes layout:
instruction = 32bit(fixed length)
+---------------------------------------------+
|0-5(6bits)|6-13(8bit)|14-22(9bit)|23-31(9bit)|
|==========+==========+===========+===========|
| opcode | A | C | B |
|----------+----------+-----------+-----------|
| opcode | A | Bx(unsigned) |
|----------+----------+-----------+-----------|
| opcode | A | sBx(signed) |
+---------------------------------------------+
*/
const opInvalidInstruction = ^uint32(0)
const opSizeCode = 6
const opSizeA = 8
const opSizeB = 9
const opSizeC = 9
const opSizeBx = 18
const opSizesBx = 18
const opMaxArgsA = (1 << opSizeA) - 1
const opMaxArgsB = (1 << opSizeB) - 1
const opMaxArgsC = (1 << opSizeC) - 1
const opMaxArgBx = (1 << opSizeBx) - 1
const opMaxArgSbx = opMaxArgBx >> 1
const (
OP_MOVE int = iota /* A B R(A) := R(B) */
OP_MOVEN /* A B R(A) := R(B); followed by R(C) MOVE ops */
OP_LOADK /* A Bx R(A) := Kst(Bx) */
OP_LOADBOOL /* A B C R(A) := (Bool)B; if (C) pc++ */
OP_LOADNIL /* A B R(A) := ... := R(B) := nil */
OP_GETUPVAL /* A B R(A) := UpValue[B] */
OP_GETGLOBAL /* A Bx R(A) := Gbl[Kst(Bx)] */
OP_GETTABLE /* A B C R(A) := R(B)[RK(C)] */
OP_GETTABLEKS /* A B C R(A) := R(B)[RK(C)] ; RK(C) is constant string */
OP_SETGLOBAL /* A Bx Gbl[Kst(Bx)] := R(A) */
OP_SETUPVAL /* A B UpValue[B] := R(A) */
OP_SETTABLE /* A B C R(A)[RK(B)] := RK(C) */
OP_SETTABLEKS /* A B C R(A)[RK(B)] := RK(C) ; RK(B) is constant string */
OP_NEWTABLE /* A B C R(A) := {} (size = BC) */
OP_SELF /* A B C R(A+1) := R(B); R(A) := R(B)[RK(C)] */
OP_ADD /* A B C R(A) := RK(B) + RK(C) */
OP_SUB /* A B C R(A) := RK(B) - RK(C) */
OP_MUL /* A B C R(A) := RK(B) * RK(C) */
OP_DIV /* A B C R(A) := RK(B) / RK(C) */
OP_MOD /* A B C R(A) := RK(B) % RK(C) */
OP_POW /* A B C R(A) := RK(B) ^ RK(C) */
OP_UNM /* A B R(A) := -R(B) */
OP_NOT /* A B R(A) := not R(B) */
OP_LEN /* A B R(A) := length of R(B) */
OP_CONCAT /* A B C R(A) := R(B).. ... ..R(C) */
OP_JMP /* sBx pc+=sBx */
OP_EQ /* A B C if ((RK(B) == RK(C)) ~= A) then pc++ */
OP_LT /* A B C if ((RK(B) < RK(C)) ~= A) then pc++ */
OP_LE /* A B C if ((RK(B) <= RK(C)) ~= A) then pc++ */
OP_TEST /* A C if not (R(A) <=> C) then pc++ */
OP_TESTSET /* A B C if (R(B) <=> C) then R(A) := R(B) else pc++ */
OP_CALL /* A B C R(A) ... R(A+C-2) := R(A)(R(A+1) ... R(A+B-1)) */
OP_TAILCALL /* A B C return R(A)(R(A+1) ... R(A+B-1)) */
OP_RETURN /* A B return R(A) ... R(A+B-2) (see note) */
OP_FORLOOP /* A sBx R(A)+=R(A+2);
if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
OP_FORPREP /* A sBx R(A)-=R(A+2); pc+=sBx */
OP_TFORLOOP /* A C R(A+3) ... R(A+3+C) := R(A)(R(A+1) R(A+2));
if R(A+3) ~= nil then { pc++; R(A+2)=R(A+3); } */
OP_SETLIST /* A B C R(A)[(C-1)*FPF+i] := R(A+i) 1 <= i <= B */
OP_CLOSE /* A close all variables in the stack up to (>=) R(A)*/
OP_CLOSURE /* A Bx R(A) := closure(KPROTO[Bx] R(A) ... R(A+n)) */
OP_VARARG /* A B R(A) R(A+1) ... R(A+B-1) = vararg */
OP_NOP /* NOP */
)
const opCodeMax = OP_NOP
type opArgMode int
const (
opArgModeN opArgMode = iota
opArgModeU
opArgModeR
opArgModeK
)
type opType int
const (
opTypeABC = iota
opTypeABx
opTypeASbx
)
type opProp struct {
Name string
IsTest bool
SetRegA bool
ModeArgB opArgMode
ModeArgC opArgMode
Type opType
}
var opProps = []opProp{
opProp{"MOVE", false, true, opArgModeR, opArgModeN, opTypeABC},
opProp{"MOVEN", false, true, opArgModeR, opArgModeN, opTypeABC},
opProp{"LOADK", false, true, opArgModeK, opArgModeN, opTypeABx},
opProp{"LOADBOOL", false, true, opArgModeU, opArgModeU, opTypeABC},
opProp{"LOADNIL", false, true, opArgModeR, opArgModeN, opTypeABC},
opProp{"GETUPVAL", false, true, opArgModeU, opArgModeN, opTypeABC},
opProp{"GETGLOBAL", false, true, opArgModeK, opArgModeN, opTypeABx},
opProp{"GETTABLE", false, true, opArgModeR, opArgModeK, opTypeABC},
opProp{"GETTABLEKS", false, true, opArgModeR, opArgModeK, opTypeABC},
opProp{"SETGLOBAL", false, false, opArgModeK, opArgModeN, opTypeABx},
opProp{"SETUPVAL", false, false, opArgModeU, opArgModeN, opTypeABC},
opProp{"SETTABLE", false, false, opArgModeK, opArgModeK, opTypeABC},
opProp{"SETTABLEKS", false, false, opArgModeK, opArgModeK, opTypeABC},
opProp{"NEWTABLE", false, true, opArgModeU, opArgModeU, opTypeABC},
opProp{"SELF", false, true, opArgModeR, opArgModeK, opTypeABC},
opProp{"ADD", false, true, opArgModeK, opArgModeK, opTypeABC},
opProp{"SUB", false, true, opArgModeK, opArgModeK, opTypeABC},
opProp{"MUL", false, true, opArgModeK, opArgModeK, opTypeABC},
opProp{"DIV", false, true, opArgModeK, opArgModeK, opTypeABC},
opProp{"MOD", false, true, opArgModeK, opArgModeK, opTypeABC},
opProp{"POW", false, true, opArgModeK, opArgModeK, opTypeABC},
opProp{"UNM", false, true, opArgModeR, opArgModeN, opTypeABC},
opProp{"NOT", false, true, opArgModeR, opArgModeN, opTypeABC},
opProp{"LEN", false, true, opArgModeR, opArgModeN, opTypeABC},
opProp{"CONCAT", false, true, opArgModeR, opArgModeR, opTypeABC},
opProp{"JMP", false, false, opArgModeR, opArgModeN, opTypeASbx},
opProp{"EQ", true, false, opArgModeK, opArgModeK, opTypeABC},
opProp{"LT", true, false, opArgModeK, opArgModeK, opTypeABC},
opProp{"LE", true, false, opArgModeK, opArgModeK, opTypeABC},
opProp{"TEST", true, true, opArgModeR, opArgModeU, opTypeABC},
opProp{"TESTSET", true, true, opArgModeR, opArgModeU, opTypeABC},
opProp{"CALL", false, true, opArgModeU, opArgModeU, opTypeABC},
opProp{"TAILCALL", false, true, opArgModeU, opArgModeU, opTypeABC},
opProp{"RETURN", false, false, opArgModeU, opArgModeN, opTypeABC},
opProp{"FORLOOP", false, true, opArgModeR, opArgModeN, opTypeASbx},
opProp{"FORPREP", false, true, opArgModeR, opArgModeN, opTypeASbx},
opProp{"TFORLOOP", true, false, opArgModeN, opArgModeU, opTypeABC},
opProp{"SETLIST", false, false, opArgModeU, opArgModeU, opTypeABC},
opProp{"CLOSE", false, false, opArgModeN, opArgModeN, opTypeABC},
opProp{"CLOSURE", false, true, opArgModeU, opArgModeN, opTypeABx},
opProp{"VARARG", false, true, opArgModeU, opArgModeN, opTypeABC},
opProp{"NOP", false, false, opArgModeR, opArgModeN, opTypeASbx},
}
func opGetOpCode(inst uint32) int {
return int(inst >> 26)
}
func opSetOpCode(inst *uint32, opcode int) {
*inst = (*inst & 0x3ffffff) | uint32(opcode<<26)
}
func opGetArgA(inst uint32) int {
return int(inst>>18) & 0xff
}
func opSetArgA(inst *uint32, arg int) {
*inst = (*inst & 0xfc03ffff) | uint32((arg&0xff)<<18)
}
func opGetArgB(inst uint32) int {
return int(inst & 0x1ff)
}
func opSetArgB(inst *uint32, arg int) {
*inst = (*inst & 0xfffffe00) | uint32(arg&0x1ff)
}
func opGetArgC(inst uint32) int {
return int(inst>>9) & 0x1ff
}
func opSetArgC(inst *uint32, arg int) {
*inst = (*inst & 0xfffc01ff) | uint32((arg&0x1ff)<<9)
}
func opGetArgBx(inst uint32) int {
return int(inst & 0x3ffff)
}
func opSetArgBx(inst *uint32, arg int) {
*inst = (*inst & 0xfffc0000) | uint32(arg&0x3ffff)
}
func opGetArgSbx(inst uint32) int {
return opGetArgBx(inst) - opMaxArgSbx
}
func opSetArgSbx(inst *uint32, arg int) {
opSetArgBx(inst, arg+opMaxArgSbx)
}
func opCreateABC(op int, a int, b int, c int) uint32 {
var inst uint32 = 0
opSetOpCode(&inst, op)
opSetArgA(&inst, a)
opSetArgB(&inst, b)
opSetArgC(&inst, c)
return inst
}
func opCreateABx(op int, a int, bx int) uint32 {
var inst uint32 = 0
opSetOpCode(&inst, op)
opSetArgA(&inst, a)
opSetArgBx(&inst, bx)
return inst
}
func opCreateASbx(op int, a int, sbx int) uint32 {
var inst uint32 = 0
opSetOpCode(&inst, op)
opSetArgA(&inst, a)
opSetArgSbx(&inst, sbx)
return inst
}
const opBitRk = 1 << (opSizeB - 1)
const opMaxIndexRk = opBitRk - 1
func opIsK(value int) bool {
return bool((value & opBitRk) != 0)
}
func opIndexK(value int) int {
return value & ^opBitRk
}
func opRkAsk(value int) int {
return value | opBitRk
}
func opToString(inst uint32) string {
op := opGetOpCode(inst)
if op > opCodeMax {
return ""
}
prop := &(opProps[op])
arga := opGetArgA(inst)
argb := opGetArgB(inst)
argc := opGetArgC(inst)
argbx := opGetArgBx(inst)
argsbx := opGetArgSbx(inst)
buf := ""
switch prop.Type {
case opTypeABC:
buf = fmt.Sprintf("%s | %d, %d, %d", prop.Name, arga, argb, argc)
case opTypeABx:
buf = fmt.Sprintf("%s | %d, %d", prop.Name, arga, argbx)
case opTypeASbx:
buf = fmt.Sprintf("%s | %d, %d", prop.Name, arga, argsbx)
}
switch op {
case OP_MOVE:
buf += fmt.Sprintf("; R(%v) := R(%v)", arga, argb)
case OP_MOVEN:
buf += fmt.Sprintf("; R(%v) := R(%v); followed by %v MOVE ops", arga, argb, argc)
case OP_LOADK:
buf += fmt.Sprintf("; R(%v) := Kst(%v)", arga, argbx)
case OP_LOADBOOL:
buf += fmt.Sprintf("; R(%v) := (Bool)%v; if (%v) pc++", arga, argb, argc)
case OP_LOADNIL:
buf += fmt.Sprintf("; R(%v) := ... := R(%v) := nil", arga, argb)
case OP_GETUPVAL:
buf += fmt.Sprintf("; R(%v) := UpValue[%v]", arga, argb)
case OP_GETGLOBAL:
buf += fmt.Sprintf("; R(%v) := Gbl[Kst(%v)]", arga, argbx)
case OP_GETTABLE:
buf += fmt.Sprintf("; R(%v) := R(%v)[RK(%v)]", arga, argb, argc)
case OP_GETTABLEKS:
buf += fmt.Sprintf("; R(%v) := R(%v)[RK(%v)] ; RK(%v) is constant string", arga, argb, argc, argc)
case OP_SETGLOBAL:
buf += fmt.Sprintf("; Gbl[Kst(%v)] := R(%v)", argbx, arga)
case OP_SETUPVAL:
buf += fmt.Sprintf("; UpValue[%v] := R(%v)", argb, arga)
case OP_SETTABLE:
buf += fmt.Sprintf("; R(%v)[RK(%v)] := RK(%v)", arga, argb, argc)
case OP_SETTABLEKS:
buf += fmt.Sprintf("; R(%v)[RK(%v)] := RK(%v) ; RK(%v) is constant string", arga, argb, argc, argb)
case OP_NEWTABLE:
buf += fmt.Sprintf("; R(%v) := {} (size = BC)", arga)
case OP_SELF:
buf += fmt.Sprintf("; R(%v+1) := R(%v); R(%v) := R(%v)[RK(%v)]", arga, argb, arga, argb, argc)
case OP_ADD:
buf += fmt.Sprintf("; R(%v) := RK(%v) + RK(%v)", arga, argb, argc)
case OP_SUB:
buf += fmt.Sprintf("; R(%v) := RK(%v) - RK(%v)", arga, argb, argc)
case OP_MUL:
buf += fmt.Sprintf("; R(%v) := RK(%v) * RK(%v)", arga, argb, argc)
case OP_DIV:
buf += fmt.Sprintf("; R(%v) := RK(%v) / RK(%v)", arga, argb, argc)
case OP_MOD:
buf += fmt.Sprintf("; R(%v) := RK(%v) %% RK(%v)", arga, argb, argc)
case OP_POW:
buf += fmt.Sprintf("; R(%v) := RK(%v) ^ RK(%v)", arga, argb, argc)
case OP_UNM:
buf += fmt.Sprintf("; R(%v) := -R(%v)", arga, argb)
case OP_NOT:
buf += fmt.Sprintf("; R(%v) := not R(%v)", arga, argb)
case OP_LEN:
buf += fmt.Sprintf("; R(%v) := length of R(%v)", arga, argb)
case OP_CONCAT:
buf += fmt.Sprintf("; R(%v) := R(%v).. ... ..R(%v)", arga, argb, argc)
case OP_JMP:
buf += fmt.Sprintf("; pc+=%v", argsbx)
case OP_EQ:
buf += fmt.Sprintf("; if ((RK(%v) == RK(%v)) ~= %v) then pc++", argb, argc, arga)
case OP_LT:
buf += fmt.Sprintf("; if ((RK(%v) < RK(%v)) ~= %v) then pc++", argb, argc, arga)
case OP_LE:
buf += fmt.Sprintf("; if ((RK(%v) <= RK(%v)) ~= %v) then pc++", argb, argc, arga)
case OP_TEST:
buf += fmt.Sprintf("; if not (R(%v) <=> %v) then pc++", arga, argc)
case OP_TESTSET:
buf += fmt.Sprintf("; if (R(%v) <=> %v) then R(%v) := R(%v) else pc++", argb, argc, arga, argb)
case OP_CALL:
buf += fmt.Sprintf("; R(%v) ... R(%v+%v-2) := R(%v)(R(%v+1) ... R(%v+%v-1))", arga, arga, argc, arga, arga, arga, argb)
case OP_TAILCALL:
buf += fmt.Sprintf("; return R(%v)(R(%v+1) ... R(%v+%v-1))", arga, arga, arga, argb)
case OP_RETURN:
buf += fmt.Sprintf("; return R(%v) ... R(%v+%v-2)", arga, arga, argb)
case OP_FORLOOP:
buf += fmt.Sprintf("; R(%v)+=R(%v+2); if R(%v) <?= R(%v+1) then { pc+=%v; R(%v+3)=R(%v) }", arga, arga, arga, arga, argsbx, arga, arga)
case OP_FORPREP:
buf += fmt.Sprintf("; R(%v)-=R(%v+2); pc+=%v", arga, arga, argsbx)
case OP_TFORLOOP:
buf += fmt.Sprintf("; R(%v+3) ... R(%v+3+%v) := R(%v)(R(%v+1) R(%v+2)); if R(%v+3) ~= nil then { pc++; R(%v+2)=R(%v+3); }", arga, arga, argc, arga, arga, arga, arga, arga, arga)
case OP_SETLIST:
buf += fmt.Sprintf("; R(%v)[(%v-1)*FPF+i] := R(%v+i) 1 <= i <= %v", arga, argc, arga, argb)
case OP_CLOSE:
buf += fmt.Sprintf("; close all variables in the stack up to (>=) R(%v)", arga)
case OP_CLOSURE:
buf += fmt.Sprintf("; R(%v) := closure(KPROTO[%v] R(%v) ... R(%v+n))", arga, argbx, arga, arga)
case OP_VARARG:
buf += fmt.Sprintf("; R(%v) R(%v+1) ... R(%v+%v-1) = vararg", arga, arga, arga, argb)
case OP_NOP:
/* nothing to do */
}
return buf
}
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