1

#include "stdafx.h"

     2

     3

#undef RDTSC_AVAILABLE

     4

     5

/* rdtsc for MSC_VER, uses simple inline assembly, or _rdtsc

     6

 * from external win64.asm because VS2005 does not support inline assembly */

     7

#if defined(_MSC_VER) && !defined(RDTSC_AVAILABLE)

     8

# if defined (_M_AMD64)

     9

extern uint64 _rdtsc(void);

    10

#	else

    11

uint64 _declspec(naked) _rdtsc(void)

    12

{

    13

	_asm {

    14

		rdtsc

    15

		ret

    16

	}

    17

}

    18

# endif

    19

# define RDTSC_AVAILABLE

    20

#endif

    21

    22

/* rdtsc for OS/2. Hopefully this works, who knows */

    23

#if defined (__WATCOMC__) && !defined(RDTSC_AVAILABLE)

    24

unsigned __int64 _rdtsc( void);

    25

# pragma aux _rdtsc = 0x0F 0x31 value [edx eax] parm nomemory modify exact [edx eax] nomemory;

    26

# define RDTSC_AVAILABLE

    27

#endif

    28

    29

/* rdtsc for all other *nix-en (hopefully). Use GCC syntax */

    30

#if defined(__i386__) || defined(__x86_64__) && !defined(RDTSC_AVAILABLE)

    31

uint64 _rdtsc(void)

    32

{

    33

	uint32 high, low;

    34

	__asm__ __volatile__ ("rdtsc" : "=a" (low), "=d" (high));

    35

	return ((uint64)high << 32) | low;

    36

}

    37

# define RDTSC_AVAILABLE

    38

#endif

    39

    40

/* rdtsc for PPC which has this not */

    41

#if defined(__POWERPC__) && !defined(RDTSC_AVAILABLE)

    42

uint64 _rdtsc(void)

    43

{

    44

	uint32 high = 0, high2 = 0, low;

    45

	/* PPC does not have rdtsc, so we cheat by reading the two 32-bit time-counters

    46

	 * it has, 'Move From Time Base (Upper)'. Since these are two reads, in the

    47

	 * very unlikely event that the lower part overflows to the upper part while we

    48

	 * read it; we double-check and reread the registers */

    49

	asm volatile (

    50

				  "mftbu %0\n"

    51

				  "mftb %1\n"

    52

				  "mftbu %2\n"

    53

				  "cmpw %3,%4\n"

    54

				  "bne- $-16\n"

    55

				  : "=r" (high), "=r" (low), "=r" (high2)

    56

				  : "0" (high), "2" (high2)

    57

				  );

    58

	return ((uint64)high << 32) | low;

    59

}

    60

# define RDTSC_AVAILABLE

    61

#endif

    62

    63

/* In all other cases we have no support for rdtsc. No major issue,

    64

 * you just won't be able to profile your code with TIC()/TOC() */

    65

#if !defined(RDTSC_AVAILABLE)

    66

#warning "OS has no support for rdtsc()"

    67

uint64 _rdtsc(void) {return 0;}

    68

#endif