/* -*- Mode: C; c-basic-offset:4 ; -*- */

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#ifndef MPL_TIMER_LINUX86_CYCLE_H_INCLUDED

#define MPL_TIMER_LINUX86_CYCLE_H_INCLUDED

static inline int MPL_wtime(MPL_time_t * timeval)

{

/* The rdtsc instruction is not a "serializing" instruction, so the

   processor is free to reorder it.  In order to get more accurate

   timing numbers with rdtsc, we need to put a serializing

   instruction, like cpuid, before rdtsc.  X86_64 architectures have

   the rdtscp instruction which is synchronizing, we use this when we

   can. */

#ifdef MPL_LINUX86_CYCLE_RDTSCP

    unsigned long long lower, upper, extra;

    __asm__ __volatile__("rdtscp\n":"=a"(lower), "=d"(upper), "=c"(extra));

    *timeval = (upper << 32) + lower;

#elif defined(MPL_LINUX86_CYCLE_CPUID_RDTSC64)

    unsigned long long lower, upper;

    __asm__ __volatile__("cpuid ; rdtsc":"=a"(lower), "=d"(upper)::"ebx", "ecx");

    *timeval = (upper << 32) + lower;

#elif  defined(MPL_LINUX86_CYCLE_CPUID_RDTSC32)

    __asm__ __volatile__("cpuid ; rdtsc":"=A"(*timeval)::"ebx", "ecx");

#elif defined(MPL_LINUX86_CYCLE_RDTSC)

/* The configure test using cpuid must have failed, try just rdtsc by itself */

    __asm__ __volatile__("rdtsc":"=A"(*timeval));

#else

#error Dont know which Linux timer to use

#endif

    return MPL_TIMER_SUCCESS;

}

#endif /* MPL_TIMER_LINUX86_CYCLE_H_INCLUDED */