/* compiled with -msse2, etc*/

//#include <mmintrin.h>  /* MMX */
//#include <xmmintrin.h> /* SSE */
#include <emmintrin.h> /* SSE2 */
//#include <pmmintrin.h> /* SSE3 */
//#include <tmmintrin.h> /* SSSE3 */
//#include <smmintrin.h> /* SSE4.2 SSE4.1 */

#include<sys/time.h>
#include<time.h>
#include<stdio.h>
typedef unsigned long long ticks;

static __inline__ ticks getticks(void)
{
     unsigned a, d;
     asm("cpuid");
     asm volatile("rdtsc" : "=a" (a), "=d" (d));

     return (((ticks)a) | (((ticks)d) << 32));
}

/* plain version x = a*x */
void sapxy(int n, float a, float *x)
{
  int i;
  for (i=0; i<n; i++) x[i] = x[i]*a;
}

/* sse version */

void sse_sapxy(int n, float a, float *x)
{
  float aa[4];
  __m128 v_a;
  __m128 *v_x;
  int i;

  aa[0] = aa[1] = aa[2] = aa[3] = a;
  v_a = _mm_load_ps(aa);
  v_x = (__m128 *)x;

  for (i=0; i<n-3; i+=4) {
    *v_x = _mm_mul_ps(*v_x, v_a);
    v_x++;
  }
  for (;i<n; i++)
    x[i] = x[i] * a;
}

float a[1000000];
float b[1000000];

void print_duration(struct timespec *b, struct timespec *c)
{
	long long r = c->tv_nsec - b->tv_nsec;
        r += ((long long)(c->tv_sec - b->tv_sec) ) * 1000000000;
	printf("duration = %lld nanoseconds\n", r);
}

main()
{
  unsigned long long int t1, t2, t3;
  struct timespec bb, ee;

  int i, j;

  for (i=0; i<1000000; i++) {
    a[i] = i*1.0;
    b[i] = i*1.0;
  }

  //  t1 = getticks();
  clock_gettime(CLOCK_THREAD_CPUTIME_ID, &bb);  

  sapxy(1000000, 3.14159, a);

  //  t2 = getticks();
  //printf("time = %lld\n", t2-t1);
  clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ee);  
  print_duration(&bb, &ee);

  //  t1 = getticks();
  clock_gettime(CLOCK_THREAD_CPUTIME_ID, &bb);  

  sse_sapxy(1000000, 3.14159, b);
  //  t2 = getticks();
  clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ee);  
  print_duration(&bb, &ee);

  //  printf("time = %lld\n", t2-t1);
  for (i=0; i<999999; i++) {
    if (a[i] != b[i]) {printf("Wrong.\n"); exit(0);}
    //printf("%d %f %f\n", i, z3[i], z4[i]);
  }
  printf("Correct, results matched.\n");
  return 0;
}