ref: 2b4a488762eb85495d0001cfa689f12b2c746a7a
dir: /sys/src/libc/arm/atom.s/
#define CLREX WORD $0xf57ff01f #define LDREX(a,r) WORD $(0xe<<28|0x01900f9f | (a)<<16 | (r)<<12) /* `The order of operands is from left to right in dataflow order' - asm man */ #define STREX(v,a,r) WORD $(0xe<<28|0x01800f90 | (a)<<16 | (r)<<12 | (v)<<0) /* * int cas(ulong *p, ulong ov, ulong nv); */ TEXT cas+0(SB),0,$0 /* r0 holds p */ TEXT casp+0(SB),0,$0 /* r0 holds p */ MOVW ov+4(FP), R1 MOVW nv+8(FP), R2 spincas: LDREX(0,3) /* LDREX 0(R0),R3 */ CMP.S R3, R1 BNE fail STREX(2,0,4) /* STREX 0(R0),R2,R4 */ CMP.S $0, R4 BNE spincas MOVW $1, R0 RET fail: CLREX MOVW $0, R0 RET TEXT _xinc(SB), $0 /* void _xinc(long *); */ TEXT ainc(SB), $0 /* long ainc(long *); */ spinainc: LDREX(0,3) /* LDREX 0(R0),R3 */ ADD $1,R3 STREX(3,0,4) /* STREX 0(R0),R3,R4 */ CMP.S $0, R4 BNE spinainc MOVW R3, R0 RET TEXT _xdec(SB), $0 /* long _xdec(long *); */ TEXT adec(SB), $0 /* long adec(long *); */ spinadec: LDREX(0,3) /* LDREX 0(R0),R3 */ SUB $1,R3 STREX(3,0,4) /* STREX 0(R0),R3,R4 */ CMP.S $0, R4 BNE spinadec MOVW R3, R0 RET TEXT loadlinked(SB), $0 /* long loadlinked(long *); */ LDREX(0,0) /* LDREX 0(R0),R0 */ RET TEXT storecond(SB), $0 /* int storecond(long *, long); */ MOVW ov+4(FP), R3 STREX(3,0,0) /* STREX 0(R0),R3,R0 */ RSB $1, R0 RET