/* simplewritespeed.c - simplistic memory writespeed test
 * Written by Harry Sintonen <sintonen@iki.fi>. Public Domain.
 *
 * Compile: gcc -O2 simplewritespeed.c -o simplewritespeed
 *
 * If you run this under multitasking environment, please make
 * sure there are no busy background processes eating CPU time.
 * Even with idle systems, results are probably slightly slower
 * than possible under optimum conditions.
 *
 * WARNING: You must fix BASE and SIZE variables below before
 * compiling. The memory located at BASE will be trashed by
 * this test. I told you this was simple. :)
 *
 */
#include <sys/time.h>
#include <time.h>
#include <stdio.h>

#define MEG    (1024 * 1024)

/* NOTE: These MUST be fixed! */
#define BASE   0xe8000000   /* memory base */
#define SIZE   16 * MEG     /* size of the memory area to write */
#define ROUNDS 32           /* number of loops */

/* Adjust for your target CPU. These are ok for 32bit CPUs */
typedef unsigned int       u32t;
typedef unsigned long long u64t;
typedef double             f64t;

int main(void)
{
  struct timeval beg, end;
  f64t *ptr;
  u32t totalsize;
  u64t totaltime;
  u32t speed;
  int i;

  gettimeofday(&beg, NULL);

  for (i = 0; i < ROUNDS; i++)
  {
    u32t lcnt = SIZE / (sizeof(f64t) * 4);
    ptr = (f64t *) BASE;
    do
    {
      *ptr++ = 123456.789;
      *ptr++ = 123456.789;
      *ptr++ = 123456.789;
      *ptr++ = 123456.789;
    } while (--lcnt);
  }

  gettimeofday(&end, NULL);

  totalsize = SIZE * ROUNDS / MEG;

  totaltime = ((u64t) end.tv_sec * 1000000 + end.tv_usec) -
              ((u64t) beg.tv_sec * 1000000 + beg.tv_usec);

  speed = (u64t) totalsize * 100000000 / totaltime;

  printf("%u MB written in %u.%06u seconds, %u.%02u MB/s\n",
         totalsize,
         (u32t) (totaltime / 1000000), (u32t) (totaltime % 1000000),
         speed / 100, speed % 100);

  return 0;
}