ref: d99a4ed1b8d06a5163b1cceb8d4cfe285faa70b2
dir: /sys/src/libthread/xincamd64.s/
/*TEXT xadd(SB),$0 /* long xadd(long *, long); */ /* MOVL i+8(FP),AX /* LOCK /* XADDL AX, (RARG) /* RET */ TEXT _xinc(SB),$0 /* void _xinc(long *); */ LOCK; INCL 0(RARG) RET TEXT _xdec(SB),$0 /* long _xdec(long *); */ MOVL $0, AX MOVL $1, BX LOCK; DECL 0(RARG) CMOVLNE BX, AX RET