rdtsc.h

/* This is the RDTSC timer.
 * RDTSC is an instruction on several Intel and compatible CPUs that Reads the
 * Time Stamp Counter. The Intel manuals contain more information.
 */

#ifndef RDTSC_H_INCLUDED
#define RDTSC_H_INCLUDED

#define COUNTER_LO(a) ((a).int32.lo)
#define COUNTER_HI(a) ((a).int32.hi)
#define COUNTER_VAL(a) ((a).int64)

#define COUNTER(a) \
	((double)COUNTER_VAL(a))

#define COUNTER_DIFF(a,b) \
	(COUNTER(a)-COUNTER(b))

/* ==================== GNU C and possibly other UNIX compilers ===================== */
#ifndef WIN32

#if defined(__GNUC__) || defined(__linux__)
#define VOLATILE __volatile__
#define ASM __asm__
#else
/* if we're neither compiling with gcc or under linux, we can hope
 * the following lines work, they probably won't */
#define ASM asm
#define VOLATILE 
#endif

#define myInt64 unsigned long long
#define INT32 unsigned int

typedef union
{       myInt64 int64;
        struct {INT32 lo, hi;} int32;
} tsc_counter;

#if defined(__ia64__)
	#if defined(__INTEL_COMPILER)
		#define RDTSC(tsc) (tsc).int64=__getReg(3116)
	#else
		#define RDTSC(tsc) ASM VOLATILE ("mov %0=ar.itc" : "=r" ((tsc).int64) )
	#endif

	#define CPUID() do{/*No need for serialization on Itanium*/}while(0)
#else
	#define RDTSC(cpu_c) \
		ASM VOLATILE ("rdtsc" : "=a" ((cpu_c).int32.lo), "=d"((cpu_c).int32.hi))
	#define CPUID() \
		ASM VOLATILE ("cpuid" : : "a" (0) : "bx", "cx", "dx" )
#endif

/* ======================== WIN32 ======================= */
#else

	#define myInt64 signed __int64
	#define INT32 unsigned __int32

	typedef union
	{       myInt64 int64;
			struct {INT32 lo, hi;} int32;
	} tsc_counter;

	#define RDTSC(cpu_c)   \
	{       __asm rdtsc    \
			__asm mov (cpu_c).int32.lo,eax  \
			__asm mov (cpu_c).int32.hi,edx  \
	}

	#define CPUID() \
	{ \
		__asm mov eax, 0 \
		__asm cpuid \
	}

#endif

#endif