/*
  cycles.c
  David Rowe
  11/5/06

  Test program to measure execution cycles of DSP operations on the
  Blackfin.  Thanks to Jean-Marc Valin of Speex for helping with
  Blackfin code samples and comments.
*/

#include <stdio.h>

void test1();
void test2();
void test3();
void test4();

#define N 100 /* size of vectors                           */
#define M 10  /* number of times to repeat tests           */

int before;   /* cycle counter value just before test loop */
int after;    /* cycle counter value just after test loop  */

int main() {
  printf("Theoretical best case is N/2 = %d cycles\n", N/2);
  test1();
  test2();
  test3();
  test4();
  return 0;
}

/* find dot product of two vectors, C version */

int dot(short *x, short *y, int len)
{
   int i,dot;

   dot = 0;
   for(i=0; i<len; i++)
     dot += x[i] * y[i];

   return dot;
}

/* find dot product of two vectors */

int dot1(short *x, short *y, int len)
{
   int dot;

   /* Isn't it cool how you can mix C and assembler?  And gcc just
      takes care of all the fiddly little details.  Very nice */

   __asm__ 
   (
   "I0 = %3;\n\t"
   "I1 = %4;\n\t"
   "A1 = A0 = 0;\n\t"
   "R0 = [I0++] || R1 = [I1++];\n\t"
   "LOOP dot%= LC0 = %5 >> 1;\n\t"
   "LOOP_BEGIN dot%=;\n\t"
      "A1 += R0.H * R1.H, A0 += R0.L * R1.L || R0 = [I0++] || R1 = [I1++];\n\t"
   "LOOP_END dot%=;\n\t"
   "R0 = (A0 += A1);\n\t"
   "%0 = R0 >> 1;\n\t" /* correct for left shift during multiply */
   : "=&d" (dot), "=&d" (before), "=&d" (after)
   : "a" (x), "a" (y), "a" (len)
   : "I0", "I1", "A1", "A0", "R0", "R1"
   );

   return dot;
}

/* find dot product of two vectors, built in cycles measurement */

int dot2(short *x, short *y, int len)
{
   int dot;

   __asm__ 
   (
   "I0 = %3;\n\t"
   "I1 = %4;\n\t"
   "A1 = A0 = 0;\n\t"
   "R0 = [I0++] || R1 = [I1++];\n\t"
   "R2 = CYCLES;\n\t"
   "%1 = R2;\n\t"
   "LOOP dot%= LC0 = %5 >> 1;\n\t"
   "LOOP_BEGIN dot%=;\n\t"
      "A1 += R0.H * R1.H, A0 += R0.L * R1.L || R0 = [I0++] || R1 = [I1++];\n\t"
   "LOOP_END dot%=;\n\t"
   "R2 = CYCLES;\n\t"
   "%2 = R2;\n\t"
   "R0 = (A0 += A1);\n\t"
   "%0 = R0 >> 1;\n\t" /* correct for left shift during multiply */
   : "=&d" (dot), "=&d" (before), "=&d" (after)
   : "a" (x), "a" (y), "a" (len)
   : "I0", "I1", "A1", "A0", "R0", "R1", "R2"
   );

   return dot;
}

/* C-callable function to return value of CYCLES register */

int cycles() {
  int ret;

   __asm__ __volatile__ 
   (
   "%0 = CYCLES;\n\t"
   : "=&d" (ret)
   : 
   : "R1"
   );

   return ret;
}

void test1() {
  short        x[N];
  short        y[N];
  int          i,k, ret;
  unsigned int before, after;
  unsigned int time[M];  

  for(i=0; i<N; i++) {
    x[i] = 1;
    y[i] = 1;
  }

  for(k=0; k<M; k++) {
    before = cycles();
    ret = dot(x, y, N);
    after = cycles();
    time[k] = after - before;
  }

  printf("Test 1: Vanilla C\n");
  printf("  ret = %d: run time:\n  ",ret);
  for(k=0; k<M; k++)
    printf("%u ", time[k]);
  printf("\n");
}

void test2() {
  short        x[N];
  short        y[N];
  int          i,k, ret;
  unsigned int before, after;
  unsigned int time[M];  

  for(i=0; i<N; i++) {
    x[i] = 1;
    y[i] = 1;
  }

  for(k=0; k<M; k++) {
    before = cycles();
    ret = dot1(x, y, N);
    after = cycles();
    time[k] = after - before;
  }

  printf("Test 2: data in external memory, outboard cycles function\n");
  printf("  ret = %d: run time:\n  ",ret);
  for(k=0; k<M; k++)
    printf("%u ", time[k]);
  printf("\n");
}

void test3() {
  short        x[N];
  short        y[N];
  int          i,k, ret;
  unsigned int time[M];  

  for(i=0; i<N; i++) {
    x[i] = 1;
    y[i] = 1;
  }

  for(k=0; k<M; k++) {
    ret = dot2(x, y, N);
    time[k] = after - before;
  }

  printf("Test 3: data in external memory, inboard cycles\n");
  printf("  ret = %d: run time:\n ",ret);
  for(k=0; k<M; k++)
    printf("%u ", time[k]);
  printf("\n");
}

void test4() {
  /* I know, I know - this is very naughty :-) */
  short       *x=(short*)0xff904000 - N*sizeof(short); /* Top of Data B SRAM */
  short       *y=(short*)0xff804000 - N*sizeof(short); /* Top of Data A SRAM */

  int          i,k, ret;
  unsigned int time[M];  

  for(i=0; i<N; i++) {
    x[i] = 1;
    y[i] = 1;
  }

  for(k=0; k<M; k++) {
    ret = dot2(x, y, N);
    time[k] = after - before;
  }

  printf("Test 4: data in internal memory, inboard cycles\n");
  printf("  ret = %d: run time:\n  ",ret);
  for(k=0; k<M; k++)
    printf("%u ", time[k]);
  printf("\n");

}