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Diffstat (limited to 'src/pkg/runtime/amd64/asm.s')
| -rw-r--r-- | src/pkg/runtime/amd64/asm.s | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/pkg/runtime/amd64/asm.s b/src/pkg/runtime/amd64/asm.s index b6642c13c..cc05435f7 100644 --- a/src/pkg/runtime/amd64/asm.s +++ b/src/pkg/runtime/amd64/asm.s @@ -317,6 +317,26 @@ TEXT runtime·cas(SB), 7, $0 MOVL $1, AX RET +// bool casp(void **val, void *old, void *new) +// Atomically: +// if(*val == old){ +// *val = new; +// return 1; +// } else +// return 0; +TEXT runtime·casp(SB), 7, $0 + MOVQ 8(SP), BX + MOVQ 16(SP), AX + MOVQ 24(SP), CX + LOCK + CMPXCHGQ CX, 0(BX) + JZ 3(PC) + MOVL $0, AX + RET + MOVL $1, AX + RET + + // void jmpdefer(fn, sp); // called from deferreturn. // 1. pop the caller |