forked from Shopify/go-lua
/
instructions.go
269 lines (247 loc) · 7.62 KB
/
instructions.go
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package lua
import "fmt"
type opCode uint
const (
iABC int = iota
iABx
iAsBx
iAx
)
const (
opMove opCode = iota
opLoadConstant
opLoadConstantEx
opLoadBool
opLoadNil
opGetUpValue
opGetTableUp
opGetTable
opSetTableUp
opSetUpValue
opSetTable
opNewTable
opSelf
opAdd
opSub
opMul
opDiv
opMod
opPow
opUnaryMinus
opNot
opLength
opConcat
opJump
opEqual
opLessThan
opLessOrEqual
opTest
opTestSet
opCall
opTailCall
opReturn
opForLoop
opForPrep
opTForCall
opTForLoop
opSetList
opClosure
opVarArg
opExtraArg
)
var opNames = []string{
"MOVE",
"LOADK",
"LOADKX",
"LOADBOOL",
"LOADNIL",
"GETUPVAL",
"GETTABUP",
"GETTABLE",
"SETTABUP",
"SETUPVAL",
"SETTABLE",
"NEWTABLE",
"SELF",
"ADD",
"SUB",
"MUL",
"DIV",
"MOD",
"POW",
"UNM",
"NOT",
"LEN",
"CONCAT",
"JMP",
"EQ",
"LT",
"LE",
"TEST",
"TESTSET",
"CALL",
"TAILCALL",
"RETURN",
"FORLOOP",
"FORPREP",
"TFORCALL",
"TFORLOOP",
"SETLIST",
"CLOSURE",
"VARARG",
"EXTRAARG",
}
const (
sizeC = 9
sizeB = 9
sizeBx = sizeC + sizeB
sizeA = 8
sizeAx = sizeC + sizeB + sizeA
sizeOp = 6
posOp = 0
posA = posOp + sizeOp
posC = posA + sizeA
posB = posC + sizeC
posBx = posC
posAx = posA
bitRK = 1 << (sizeB - 1)
maxIndexRK = bitRK - 1
maxArgAx = 1<<sizeAx - 1
maxArgBx = 1<<sizeBx - 1
maxArgSBx = maxArgBx >> 1 // sBx is signed
maxArgA = 1<<sizeA - 1
maxArgB = 1<<sizeB - 1
maxArgC = 1<<sizeC - 1
listItemsPerFlush = 50 // # list items to accumulate before a setList instruction
)
type instruction uint32
func isConstant(x int) bool { return 0 != x&bitRK }
func constantIndex(r int) int { return r & ^bitRK }
func asConstant(r int) int { return r | bitRK }
// creates a mask with 'n' 1 bits at position 'p'
func mask1(n, p uint) instruction { return ^(^instruction(0) << n) << p }
// creates a mask with 'n' 0 bits at position 'p'
func mask0(n, p uint) instruction { return ^mask1(n, p) }
func (i instruction) opCode() opCode { return opCode(i >> posOp & (1<<sizeOp - 1)) }
func (i instruction) arg(pos, size uint) int { return int(i >> pos & mask1(size, 0)) }
func (i *instruction) setOpCode(op opCode) { i.setArg(posOp, sizeOp, int(op)) }
func (i *instruction) setArg(pos, size uint, arg int) {
*i = *i&mask0(size, pos) | instruction(arg)<<pos&mask1(size, pos)
}
// Note: the gc optimizer cannot inline through multiple function calls. Manually inline for now.
// func (i instruction) a() int { return i.arg(posA, sizeA) }
// func (i instruction) b() int { return i.arg(posB, sizeB) }
// func (i instruction) c() int { return i.arg(posC, sizeC) }
// func (i instruction) bx() int { return i.arg(posBx, sizeBx) }
// func (i instruction) ax() int { return i.arg(posAx, sizeAx) }
// func (i instruction) sbx() int { return i.bx() - maxArgSBx }
func (i instruction) a() int { return int(i >> posA & maxArgA) }
func (i instruction) b() int { return int(i >> posB & maxArgB) }
func (i instruction) c() int { return int(i >> posC & maxArgC) }
func (i instruction) bx() int { return int(i >> posBx & maxArgBx) }
func (i instruction) ax() int { return int(i >> posAx & maxArgAx) }
func (i instruction) sbx() int { return int(i>>posBx&maxArgBx) - maxArgSBx }
func (i *instruction) setA(arg int) { i.setArg(posA, sizeA, arg) }
func (i *instruction) setB(arg int) { i.setArg(posB, sizeB, arg) }
func (i *instruction) setC(arg int) { i.setArg(posC, sizeC, arg) }
func (i *instruction) setBx(arg int) { i.setArg(posBx, sizeBx, arg) }
func (i *instruction) setAx(arg int) { i.setArg(posAx, sizeAx, arg) }
func (i *instruction) setSBx(arg int) { i.setArg(posBx, sizeBx, arg+maxArgSBx) }
func createABC(op opCode, a, b, c int) instruction {
return instruction(op)<<posOp |
instruction(a)<<posA |
instruction(b)<<posB |
instruction(c)<<posC
}
func createABx(op opCode, a, bx int) instruction {
return instruction(op)<<posOp |
instruction(a)<<posA |
instruction(bx)<<posBx
}
func createAx(op opCode, a int) instruction { return instruction(op)<<posOp | instruction(a)<<posAx }
func (i instruction) String() string {
op := i.opCode()
s := opNames[op]
switch opMode(op) {
case iABC:
s = fmt.Sprintf("%s %d", s, i.a())
if bMode(op) == opArgK && isConstant(i.b()) {
s = fmt.Sprintf("%s constant %d", s, constantIndex(i.b()))
} else if bMode(op) != opArgN {
s = fmt.Sprintf("%s %d", s, i.b())
}
if cMode(op) == opArgK && isConstant(i.c()) {
s = fmt.Sprintf("%s constant %d", s, constantIndex(i.c()))
} else if cMode(op) != opArgN {
s = fmt.Sprintf("%s %d", s, i.c())
}
case iAsBx:
s = fmt.Sprintf("%s %d", s, i.a())
if bMode(op) != opArgN {
s = fmt.Sprintf("%s %d", s, i.sbx())
}
case iABx:
s = fmt.Sprintf("%s %d", s, i.a())
if bMode(op) != opArgN {
s = fmt.Sprintf("%s %d", s, i.bx())
}
case iAx:
s = fmt.Sprintf("%s %d", s, i.ax())
}
return s
}
func opmode(t, a, b, c, m int) byte { return byte(t<<7 | a<<6 | b<<4 | c<<2 | m) }
const (
opArgN = iota // argument is not used
opArgU // argument is used
opArgR // argument is a register or a jump offset
opArgK // argument is a constant or register/constant
)
func opMode(m opCode) int { return int(opModes[m] & 3) }
func bMode(m opCode) byte { return (opModes[m] >> 4) & 3 }
func cMode(m opCode) byte { return (opModes[m] >> 2) & 3 }
func testAMode(m opCode) bool { return opModes[m]&(1<<6) != 0 }
func testTMode(m opCode) bool { return opModes[m]&(1<<7) != 0 }
var opModes []byte = []byte{
// T A B C mode opcode
opmode(0, 1, opArgR, opArgN, iABC), // opMove
opmode(0, 1, opArgK, opArgN, iABx), // opLoadConstant
opmode(0, 1, opArgN, opArgN, iABx), // opLoadConstantEx
opmode(0, 1, opArgU, opArgU, iABC), // opLoadBool
opmode(0, 1, opArgU, opArgN, iABC), // opLoadNil
opmode(0, 1, opArgU, opArgN, iABC), // opGetUpValue
opmode(0, 1, opArgU, opArgK, iABC), // opGetTableUp
opmode(0, 1, opArgR, opArgK, iABC), // opGetTable
opmode(0, 0, opArgK, opArgK, iABC), // opSetTableUp
opmode(0, 0, opArgU, opArgN, iABC), // opSetUpValue
opmode(0, 0, opArgK, opArgK, iABC), // opSetTable
opmode(0, 1, opArgU, opArgU, iABC), // opNewTable
opmode(0, 1, opArgR, opArgK, iABC), // opSelf
opmode(0, 1, opArgK, opArgK, iABC), // opAdd
opmode(0, 1, opArgK, opArgK, iABC), // opSub
opmode(0, 1, opArgK, opArgK, iABC), // opMul
opmode(0, 1, opArgK, opArgK, iABC), // opDiv
opmode(0, 1, opArgK, opArgK, iABC), // opMod
opmode(0, 1, opArgK, opArgK, iABC), // opPow
opmode(0, 1, opArgR, opArgN, iABC), // opUnaryMinus
opmode(0, 1, opArgR, opArgN, iABC), // opNot
opmode(0, 1, opArgR, opArgN, iABC), // opLength
opmode(0, 1, opArgR, opArgR, iABC), // opConcat
opmode(0, 0, opArgR, opArgN, iAsBx), // opJump
opmode(1, 0, opArgK, opArgK, iABC), // opEqual
opmode(1, 0, opArgK, opArgK, iABC), // opLessThan
opmode(1, 0, opArgK, opArgK, iABC), // opLessOrEqual
opmode(1, 0, opArgN, opArgU, iABC), // opTest
opmode(1, 1, opArgR, opArgU, iABC), // opTestSet
opmode(0, 1, opArgU, opArgU, iABC), // opCall
opmode(0, 1, opArgU, opArgU, iABC), // opTailCall
opmode(0, 0, opArgU, opArgN, iABC), // opReturn
opmode(0, 1, opArgR, opArgN, iAsBx), // opForLoop
opmode(0, 1, opArgR, opArgN, iAsBx), // opForPrep
opmode(0, 0, opArgN, opArgU, iABC), // opTForCall
opmode(0, 1, opArgR, opArgN, iAsBx), // opTForLoop
opmode(0, 0, opArgU, opArgU, iABC), // opSetList
opmode(0, 1, opArgU, opArgN, iABx), // opClosure
opmode(0, 1, opArgU, opArgN, iABC), // opVarArg
opmode(0, 0, opArgU, opArgU, iAx), // opExtraArg
}