Darkbyte Library

/******************************************************************************
 * CPU Speed
 * ---------
 * Author: Alan Doyle (alan.doyle@darkbyte.com)
 * Copyright: (c) 2005 Darkbyte Software
 * Release Version: 1.0
 * Date Started: 2005/08/03
 *
 * Display the current CPU Speed in MHz ( Pentium class PC's or higher ).
 * Tested under Linux, Windows 2000 and Windows XP.
 *
 ******************************************************************************
 *
 *   cpu.c is free software; you can redistribute it and/or modify
 *   it under the terms of the Lesser General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   cpu.c is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the Lesser General Public License
 *   along with cpu.c; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 ******************************************************************************/
 
#include <stdio.h>
 
#ifdef WIN32
#include <windows.h>
 
#define rdtsc(low, high)  \
	__asm \
	{ \
	__asm _emit 0x0f \
	__asm _emit 0x31 \
	__asm mov high,edx \
	__asm mov low,eax \
	}
 
void usleep( unsigned long delay )
{
	Sleep( delay / 1000 );
}
#else
#define rdtsc(low,high) \
	__asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))
#endif
 
int main( void )
{
	unsigned long startlow, starthigh;
	unsigned long endlow, endhigh;
	unsigned long delay = 500;
 
	rdtsc(startlow,starthigh);
	usleep( delay * 1000 );
	rdtsc(endlow,endhigh);
 
	printf("CPU Speed : %d MHz\n", ( ( endlow - startlow ) / ( 1000 * delay ) ) );
 
	return 0;
}