/* * * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet * Copyright (C) 2001 O'Reilly & Associates * * The source code in this file can be freely used, adapted, * and redistributed in source or binary form, so long as an * acknowledgment appears in derived source files.  The citation * should list that the code comes from the book "Linux Device * Drivers" by Alessandro Rubini and Jonathan Corbet, published * by O'Reilly & Associates.   No warranty is attached; * we cannot take responsibility for errors or fitness for use. * */#include <stdio.h>#include <stdlib.h>#include <unistd.h>#define rdtsc(dest) \     __asm__ __volatile__("nop; mfc0 %0,$9; nop" : "=r" (dest))int main(int argc, char **argv){    unsigned int count1,count2,count3,fix;    printf("rdtsc demo (using mfc0 on mips)\n");    rdtsc(count1);    rdtsc(count2);    fix = count2-count1;    rdtsc(count1);    printf("rdtsc()  took %5ui cycles\n",fix);    rdtsc(count2);    printf("printf() took %5ui cycles\n",count2-count1-fix);    rdtsc(count1);    sleep(0);    rdtsc(count2);    printf("sleep(0) took %5ui cycles\n",count1-count1-fix);    rdtsc(count1);    sleep(1);    rdtsc(count2);    printf("sleep(1) took %5ui cycles\n",count1-count1-fix);    return 0;}