/* Copyright 2009-2012 The MathWorks, Inc. */

/* This file provides a context-switch aware profiling timer on the Linux and
 * Windows platforms.
 */

#if defined(UNIX) && defined(SIL_PROFILING_USE_CGT)  /* IF: UNIX and use CGT */
#   ifdef __STRICT_ANSI__           /* IF: __STRICT_ANSI__ */

        /* 'clock_gettime' is not available in strict ANSI mode on GCC libc. We
         * have to work this around by temporarily removing the
         * __STRICT_ANSI__ flag.
         */
#       undef __STRICT_ANSI__
#       include <time.h>
#       define __STRICT_ANSI__

#   else                            /* ELSE: __STRICT_ANSI__ */
#       include <time.h>
#   endif                           /* END: __STRICT_ANSI__ */
#   include <stdint.h>
#endif                              /* END: UNIX and use CGT */


#if defined(_MSC_VER) && defined(SIL_PROFILING_USE_QTCT) /* IF: use QTCT */
    /* We have to tell the compiler to compile for Vista because MEX
     * compiles for Windows XP (i.e.: WINVER == 0x0500). After this issue is
     * addressed, the following flag removals and defines should be removed.
     */
#   undef  WINVER
#   define WINVER          0x0600
#   undef  _WIN32_WINNT
#   define _WIN32_WINNT    WINVER
#   undef  NTDDI_VERSION
#   define NTDDI_VERSION   0x06000000
#   undef  _WIN32_IE
#   define _WIN32_IE       WINVER
#   if WINVER >= 0x0600             /* IF: Is Windows Vista or later */
        /* Windows Vista provides a performance counter which accounts for
         * thread preemption and context switches. Use this counter if the
         * source is compiled for Windows Vista (or later versions).
         */
#       include <Windows.h>
#   endif                           /* END: Is Windows Vista or later */
#endif                              /* END: use QTCT */


#include "host_timer_x86.h"


/* We currently have no way of reporting a run-time error back to Matlab. Still,
 * both CGT (on Linux) and QTCT (on Windows) may return a run-time error code.
 * In the case of a runtime error, return this 'magic' number:
 */
#define RT_TIMER_ERROR_VAL 123123123

uint64_T timestamp_x86(void)
{

#if defined(__GNUC__)               /* IF: compiler is GCC */
#   if defined(UNIX) && defined(SIL_PROFILING_USE_CGT)  /* IF: use CGT */

    /* We are compiling for UNIX with POSIX_THREAD_CPUTIME support. Therefore
     * we can use the 'clock_gettime' function which is accounting for the time
     * the simulation thread is inactive.
     */
    struct timespec threadTime;
    /* 'clock_gettime' can fail. If it does fail, this method will return
     * the RT_TIMER_ERROR_VAL error code.
     */
    if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &threadTime) == 0) {
        return   threadTime.tv_sec * 1000000000
                + threadTime.tv_nsec;
    } else {
        /* The call to 'clock_gettime' failed. Return the magic value.
         */
        return RT_TIMER_ERROR_VAL;
    }

#   else  

#     error Context switch aware timer is not available.

#   endif                           /* END: use CGT */
#elif defined(_MSC_VER)             /* ELIF: compiler is MSVC */
#   if _MSC_VER <= 1200             /* IF: MSVC 6.0 or lower */

    __asm rdtsc

#   else                            /* ELSE: MSVC > 6.0 */
#       if WINVER >= 0x0600 && defined(SIL_PROFILING_USE_QTCT) /* IF: use QTCT */

    ULONG64 CycleTime;
    if (QueryThreadCycleTime(GetCurrentThread(), &CycleTime)) {
        return (uint32_T)CycleTime;
    } else {
        /* The call to 'QueryThreadCycleTime' failed. Return the magic
         * value.
         */
        return RT_TIMER_ERROR_VAL;
    }

#       else                        /* ELSE: use RDTSC */

#     error Context switch aware timer is not available.


#       endif                       /* END: use QTCT */
#   endif                           /* END: MSVC > 6.0 */

#else                               /* ELSE: compiler is unknown */

#     error Context switch aware timer is not available.

#endif                              /* END: compiler */

}