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/*

   Test integer multiply

   Use a software multiplication algorithm to compare against hardware

   calculated results

   Julius Baxter, julius@opencores.org

*/

#include "cpu-utils.h"

#include "printf.h"

static int smul_errors, umul_errors;

#define VERBOSE_TESTS 0

// Make this bigger when running on FPGA target. For simulation it's enough.

#define NUM_TESTS 2000

int

or1k_mul(int multiplicant, int multiplier)

{

  int result;

  asm ("l.mul\t%0,%1,%2" : "=r" (result) : "r" (multiplicant),

       "r" (multiplier));

  return result;

}

unsigned int

or1k_mulu(unsigned int mulidend, unsigned int mulisor)

{

  int result;

  asm ("l.mulu\t%0,%1,%2" : "=r" (result) : "r" (mulidend), "r" (mulisor));

  return result;

}

void

check_mul(int multiplicand, int multiplier, int expected_result)

{

#if VERBOSE_TESTS

  printf("l.mul 0x%.8x * 0x%.8x = (SW) 0x%.8x : ", multiplicand, multiplier,

         expected_result);

#endif

  int result =  or1k_mul(multiplicand, multiplier);

  report(result);

  if ( result != expected_result)

    {

      printf("l.mul  0x%.8x * 0x%.8x = (SW) 0x%.8x : ", multiplicand, multiplier,

             expected_result);

      printf("(HW) 0x%.8x - MISMATCH\n",result);

      smul_errors++;

    }

#if VERBOSE_TESTS

  else

    printf("OK\n");

#endif

}

void

check_mulu(unsigned int multiplicand, unsigned int multiplier,

           unsigned int expected_result)

{

#if VERBOSE_TESTS

  printf("l.mulu 0x%.8x * 0x%.8x = (SW) 0x%.8x : ", multiplicand, multiplier,

         expected_result);

#endif

  unsigned int result =  or1k_mulu(multiplicand, multiplier);

  report(result);

  if ( result != expected_result)

    {

      printf("l.mulu 0x%.8x * 0x%.8x = (SW) 0x%.8x : ", multiplicand, multiplier,

             expected_result);

      printf("(HW) 0x%.8x - MISMATCH\n",result);

      umul_errors++;

    }

#if VERBOSE_TESTS

  else

    printf("OK\n");

#endif

}

// Software implementation of multiply

unsigned int

mul_soft(unsigned int n, unsigned int d)

{

  unsigned int m = 0;

  //printf("sft: 0x%x 0x%xd\n",n,d);

  int i;

  for(i=0; i<32; i++)

    {

      //printf("bit %d: 0x%x\n",i, (((1<<i) & d)));

      if ((1<<i) & d)

        {

          m += (unsigned int) (n << i);

        }

    }

  return (unsigned int) m;

}

int

main(void)

{

#ifdef _UART_H_

  uart_init(DEFAULT_UART);

#endif

  umul_errors = 0;

  smul_errors = 0;

  int i;

  unsigned int n, d;

  unsigned int expected_result;

  i=0;

  n=0;d=0;

  while(i < NUM_TESTS)

    {

      n = rand() >> 20;

      d = (rand() >> 24);

      report(0x10101010);

      if (n&0x10) // Randomly select if we should negate n

        {

          // 2's complement of n

          n = ~n + 1;

        }

      if (d&0x80) // Randomly select if we should negate d

        {

          // 2's complement of d

          d = ~d + 1;

        }

      if ((n & 0x80000000) && (d & 0x80000000))

        expected_result = mul_soft(~(n-1), ~(d-1));

      else if ((n & 0x80000000) && !(d & 0x80000000))

        {

          expected_result = mul_soft(~(n-1), d);

          expected_result = ~expected_result + 1; // 2's complement

        }

      else if (!(n & 0x80000000) && (d & 0x80000000))

        {

          expected_result = mul_soft(n, ~(d-1));

          expected_result = ~expected_result + 1; // 2's complement

        }

      else if (!(n & 0x80000000) && !(d & 0x80000000))

        expected_result = mul_soft(n, d);

      /* Report things */

      report(n);

      report(d);

      report(expected_result);

      /* Signed mulide */

      check_mul(n, d, expected_result);

      /* Unsigned mulide test */

      /* Ensure numerator's bit 31 is clear */

      n >>= 1;

      expected_result = mul_soft(n, d);

      /* Report things */

      report(n);

      report(d);

      report(expected_result);

      /* Unsigned mulide */

      check_mulu(n, d, expected_result);

      report(i);

      i++;

    }

  printf("Integer multiply check complete\n");

  printf("Unsigned:\t%d tests\t %d errors\n",

         NUM_TESTS, umul_errors);

  printf("Signed:\t\t%d tests\t %d errors\n",

         NUM_TESTS, smul_errors);

  if ((umul_errors > 0) || (smul_errors > 0))

    report(0xbaaaaaad);

  else

    report(0x8000000d);

  return 0;

}