| // Copyright 2009 The Go Authors. All rights reserved. | |
| // Use of this source code is governed by a BSD-style | |
| // license that can be found in the LICENSE file. | |
| // func cas(val *int32, old, new int32) bool | |
| // Atomically: | |
| // if *val == old { | |
| // *val = new; | |
| // return true; | |
| // }else | |
| // return false; | |
| TEXT ·cas(SB), 7, $0 | |
| MOVQ 8(SP), BX | |
| MOVL 16(SP), AX | |
| MOVL 20(SP), CX | |
| LOCK | |
| CMPXCHGL CX, 0(BX) | |
| JZ ok | |
| MOVL $0, 24(SP) | |
| RET | |
| ok: | |
| MOVL $1, 24(SP) | |
| RET |