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[OpJumpFalse, OpAndJump, OpOrJump, OpJump], these four instructions have been changed to use 4 bytes to avoid precision loss and panic when the number of instructions exceeds the maximum of 16 bits (65535) (#433)

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Co-authored-by: 王录祥 <wanglx@smartsteps.com>
This commit is contained in:
wlxwlxwlx 2023-12-06 03:30:50 +08:00 committed by GitHub
parent 92cbb9bff0
commit 18424deb5a
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 19 additions and 11 deletions
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6
instructions.go
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@ -28,6 +28,12 @@ func MakeInstruction(opcode parser.Opcode, operands ...int) []byte {
n := uint16(o) n := uint16(o)
instruction[offset] = byte(n >> 8) instruction[offset] = byte(n >> 8)
instruction[offset+1] = byte(n) instruction[offset+1] = byte(n)
case 4:
n := uint32(o)
instruction[offset] = byte(n >> 24)
instruction[offset+1] = byte(n >> 16)
instruction[offset+2] = byte(n >> 8)
instruction[offset+3] = byte(n)
} }
offset += width offset += width
} }

10
parser/opcodes.go
View file

@ -106,10 +106,10 @@ var OpcodeOperands = [...][]int{
OpNotEqual: {}, OpNotEqual: {},
OpMinus: {}, OpMinus: {},
OpLNot: {}, OpLNot: {},
OpJumpFalsy: {2}, OpJumpFalsy: {4},
OpAndJump: {2}, OpAndJump: {4},
OpOrJump: {2}, OpOrJump: {4},
OpJump: {2}, OpJump: {4},
OpNull: {}, OpNull: {},
OpGetGlobal: {2}, OpGetGlobal: {2},
OpSetGlobal: {2}, OpSetGlobal: {2},
@ -149,6 +149,8 @@ func ReadOperands(numOperands []int, ins []byte) (operands []int, offset int) {
operands = append(operands, int(ins[offset])) operands = append(operands, int(ins[offset]))
case 2: case 2:
operands = append(operands, int(ins[offset+1])|int(ins[offset])<<8) operands = append(operands, int(ins[offset+1])|int(ins[offset])<<8)
case 4:
operands = append(operands, int(ins[offset+3])|int(ins[offset+2])<<8|int(ins[offset+1])<<16|int(ins[offset])<<24)
} }
offset += width offset += width
} }

14
vm.go
View file

@ -218,30 +218,30 @@ func (v *VM) run() {
return return
} }
case parser.OpJumpFalsy: case parser.OpJumpFalsy:
v.ip += 2 v.ip += 4
v.sp-- v.sp--
if v.stack[v.sp].IsFalsy() { if v.stack[v.sp].IsFalsy() {
pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8 pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8 | int(v.curInsts[v.ip-2])<<16 | int(v.curInsts[v.ip-3])<<24
v.ip = pos - 1 v.ip = pos - 1
} }
case parser.OpAndJump: case parser.OpAndJump:
v.ip += 2 v.ip += 4
if v.stack[v.sp-1].IsFalsy() { if v.stack[v.sp-1].IsFalsy() {
pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8 pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8 | int(v.curInsts[v.ip-2])<<16 | int(v.curInsts[v.ip-3])<<24
v.ip = pos - 1 v.ip = pos - 1
} else { } else {
v.sp-- v.sp--
} }
case parser.OpOrJump: case parser.OpOrJump:
v.ip += 2 v.ip += 4
if v.stack[v.sp-1].IsFalsy() { if v.stack[v.sp-1].IsFalsy() {
v.sp-- v.sp--
} else { } else {
pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8 pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8 | int(v.curInsts[v.ip-2])<<16 | int(v.curInsts[v.ip-3])<<24
v.ip = pos - 1 v.ip = pos - 1
} }
case parser.OpJump: case parser.OpJump:
pos := int(v.curInsts[v.ip+2]) | int(v.curInsts[v.ip+1])<<8 pos := int(v.curInsts[v.ip+4]) | int(v.curInsts[v.ip+3])<<8 | int(v.curInsts[v.ip+2])<<16 | int(v.curInsts[v.ip+1])<<24
v.ip = pos - 1 v.ip = pos - 1
case parser.OpSetGlobal: case parser.OpSetGlobal:
v.ip += 2 v.ip += 2