Save RDTSC

#include <stdint.h>
#include <stdio.h>
#include <unistd.h>

uint64_t read_time_stamp_counter() 
{
    uint32_t my_edx;
    uint32_t my_eax;
    
    asm ("cpuid\n\t"
         "rdtsc\n\t"
         "movl %%edx, %0\n\t"
         "movl %%eax, %1"
         :"=r"(my_edx), "=r"(my_eax) 
         :
         : "%eax", "%edx");
    return (((uint64_t) my_edx) << 32) | my_eax;
}

int main(int argc, char** argv) {
    uint64_t time_stamp_1 = read_time_stamp_counter();
    sleep(1);
    uint64_t cycles = read_time_stamp_counter() - time_stamp_1;
    
    printf("Cycles: %llu\n", cycles);
    printf("Estimated frequency: %.3f GHz\n", cycles / 1e9);
    
    return 0;
}