ref: a2be120ea93ae67447315da268fa336650cd5149
dir: /sys/src/libc/386/atom.s/
TEXT ainc(SB), $0 /* long ainc(long *); */ MOVL addr+0(FP), BX ainclp: MOVL (BX), AX MOVL AX, CX INCL CX LOCK BYTE $0x0F; BYTE $0xB1; BYTE $0x0B /* CMPXCHGL CX, (BX) */ JNZ ainclp MOVL CX, AX RET TEXT adec(SB), $0 /* long adec(long*); */ MOVL addr+0(FP), BX adeclp: MOVL (BX), AX MOVL AX, CX DECL CX LOCK BYTE $0x0F; BYTE $0xB1; BYTE $0x0B /* CMPXCHGL CX, (BX) */ JNZ adeclp MOVL CX, AX RET /* * int cas32(u32int *p, u32int ov, u32int nv); * int cas(uint *p, int ov, int nv); * int casp(void **p, void *ov, void *nv); * int casl(ulong *p, ulong ov, ulong nv); */ /* * CMPXCHG (CX), DX: 0000 1111 1011 000w oorr rmmm, * mmm = CX = 001; rrr = DX = 010 */ #define CMPXCHG BYTE $0x0F; BYTE $0xB1; BYTE $0x11 TEXT cas32+0(SB),0,$0 TEXT cas+0(SB),0,$0 TEXT casp+0(SB),0,$0 TEXT casl+0(SB),0,$0 MOVL p+0(FP), CX MOVL ov+4(FP), AX MOVL nv+8(FP), DX LOCK CMPXCHG JNE fail MOVL $1,AX RET fail: MOVL $0,AX RET /* * int cas64(u64int *p, u64int ov, u64int nv); */ /* * CMPXCHG64 (DI): 0000 1111 1100 0111 0000 1110, */ #define CMPXCHG64 BYTE $0x0F; BYTE $0xC7; BYTE $0x0F TEXT cas64+0(SB),0,$0 MOVL p+0(FP), DI MOVL ov+0x4(FP), AX MOVL ov+0x8(FP), DX MOVL nv+0xc(FP), BX MOVL nv+0x10(FP), CX LOCK CMPXCHG64 JNE fail MOVL $1,AX RET