ref: 02f047daee598f22e641365d01934973b14f89f3 dir: /b_amd64.s/
TEXT _tstart(SB), 1, $0 LFENCE RDTSC MOVL AX, 0(RARG) MOVL DX, 4(RARG) RET TEXT _tend(SB), 1, $0 RDTSC MOVL AX, 0(RARG) MOVL DX, 4(RARG) CPUID RET