Plan 9 from Bell Labs’s /usr/web/sources/contrib/quanstro/highprec/cycles.s
#define RDTSC BYTE $0x0F; BYTE $0x31 /* RDTSC, result in AX/DX (lo/hi) */ TEXT _cycles(SB), 1, $0 /* time stamp counter */ RDTSC MOVL vlong+0(FP), CX /* &vlong */ MOVL AX, 0(CX) /* lo */ MOVL DX, 4(CX) /* hi */ RET
