ref: 8a45afd47d2545b2d85aecf9ec5af90cba3905d3
dir: /sys/src/libc/arm64/atom.s/
/* * int cas32(u32int *p, u32int ov, u32int nv); * int cas(uint *p, int ov, int nv); * int casl(ulong *p, ulong ov, ulong nv); */ TEXT cas0(SB), 1, $-4 _cas0: CLREX MOVW $0, R0 RETURN TEXT cas32(SB), 1, $-4 TEXT cas(SB), 1, $-4 TEXT casl(SB), 1, $-4 MOVWU ov+8(FP), R1 MOVWU nv+16(FP), R2 _cas1: LDXRW (R0), R3 CMP R3, R1 BNE _cas0 STXRW R2, (R0), R4 CBNZ R4, _cas1 MOVW $1, R0 B _barrier(SB) TEXT casp(SB), 1, $-4 MOV ov+8(FP), R1 MOV nv+16(FP), R2 _casp1: LDXR (R0), R3 CMP R3, R1 BNE _cas0 STXR R2, (R0), R4 CBNZ R4, _casp1 MOVW $1, R0 B _barrier(SB) TEXT _xinc(SB), 1, $-4 /* void _xinc(long *); */ TEXT ainc(SB), 1, $-4 /* long ainc(long *); */ spinainc: LDXRW (R0), R3 ADDW $1,R3 STXRW R3, (R0), R4 CBNZ R4, spinainc MOVW R3, R0 B _barrier(SB) TEXT _xdec(SB), 1, $-4 /* long _xdec(long *); */ TEXT adec(SB), 1, $-4 /* long adec(long *); */ spinadec: LDXRW (R0), R3 SUBW $1,R3 STXRW R3, (R0), R4 CBNZ R4, spinadec MOVW R3, R0 B _barrier(SB)