rshift.c

a very popular packet of cryptography tools,it encloses the most common used algorithm and protocols

/*
Copyright 1996, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA.
*/

#include <stdio.h>
#include "gmp.h"
#include "gmp-impl.h"

#if defined (USG) || defined (__SVR4) || defined (_UNICOS) || defined (__hpux)
#include <time.h>

int
cputime ()
{
  if (CLOCKS_PER_SEC < 100000)
    return clock () * 1000 / CLOCKS_PER_SEC;
  return clock () / (CLOCKS_PER_SEC / 1000);
}
#else
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>

int
cputime ()
{
  struct rusage rus;

  getrusage (0, &rus);
  return rus.ru_utime.tv_sec * 1000 + rus.ru_utime.tv_usec / 1000;
}
#endif

#define M * 1000000

#ifndef CLOCK
#error "Don't know CLOCK of your machine"
#endif

#ifndef OPS
#define OPS (CLOCK/5)
#endif
#ifndef SIZE
#define SIZE 496
#endif
#ifndef TIMES
#define TIMES OPS/SIZE
#else
#undef OPS
#define OPS (SIZE*TIMES)
#endif

mp_limb_t
refmpn_rshift (wp, up, usize, cnt)
     register mp_ptr wp;
     register mp_srcptr up;
     mp_size_t usize;
     register unsigned int cnt;
{
  register mp_limb_t high_limb, low_limb;
  register unsigned sh_1, sh_2;
  register mp_size_t i;
  mp_limb_t retval;

#ifdef DEBUG
  if (usize == 0 || cnt == 0)
    abort ();
#endif

  sh_1 = cnt;
#if 0
  if (sh_1 == 0)
    {
      if (wp != up)
	{
	  /* Copy from low end to high end, to allow specified input/output
	     overlapping.  */
	  for (i = 0; i < usize; i++)
	    wp[i] = up[i];
	}
      return 0;
    }
#endif

  wp -= 1;
  sh_2 = BITS_PER_MP_LIMB - sh_1;
  high_limb = up[0];
  retval = high_limb << sh_2;
  low_limb = high_limb;

  for (i = 1; i < usize; i++)
    {
      high_limb = up[i];
      wp[i] = (low_limb >> sh_1) | (high_limb << sh_2);
      low_limb = high_limb;
    }
  low_limb >>= sh_1;
  wp[i] = low_limb;

  return retval;
}

#ifndef CNT
#define CNT 4
#endif

main (argc, argv)
     int argc;
     char **argv;
{
  mp_limb_t s1[SIZE];
  mp_limb_t dx[SIZE+2];
  mp_limb_t dy[SIZE+2];
  mp_limb_t cyx, cyy;
  int i;
  long t0, t;
  int test;
  int cnt = CNT;
  mp_size_t size;

  for (test = 0; ; test++)
    {
#if TIMES == 1 && ! defined (PRINT)
      if (test % (SIZE > 10000 ? 1 : 10000 / SIZE) == 0)
	{
	  printf ("\r%d", test);
	  fflush (stdout);
	}
#endif

#if TIMES == 1
      cnt = random () % (BITS_PER_MP_LIMB - 1) + 1;
#endif

#ifdef RANDOM
      size = random () % SIZE + 1;
#else
      size = SIZE;
#endif
      mpn_random2 (s1, size);

      dx[size+1] = 0x12345678;
      dy[size+1] = 0x12345678;
      dx[0] = 0x87654321;
      dy[0] = 0x87654321;

#if TIMES != 1
      mpn_random (s1, size);

#ifndef NOCHECK
      t0 = cputime();
      for (i = 0; i < TIMES; i++)
	refmpn_rshift (dx+1, s1, size, cnt);
      t = cputime() - t0;
      printf ("refmpn_rshift: %5ldms (%.2f cycles/limb)\n",
	      t, ((double) t * CLOCK) / (OPS * 1000.0));
#endif

      t0 = cputime();
      for (i = 0; i < TIMES; i++)
	mpn_rshift (dx+1, s1, size, cnt);
      t = cputime() - t0;
      printf ("mpn_rshift:    %5ldms (%.2f cycles/limb)\n",
	      t, ((double) t * CLOCK) / (OPS * 1000.0));
#endif

#ifndef NOCHECK
      mpn_random2 (s1, size);

#ifdef PRINT
      printf ("%-*d ", (int) (2 * sizeof(mp_limb_t)), cnt); mpn_print (s1, size);
#endif

      /* Put garbage in the destination.  */
      for (i = 0; i < size; i++)
	{
	  dx[i+1] = 0xdead;
	  dy[i+1] = 0xbeef;
	}

      cyx = refmpn_rshift (dx+1, s1, size, cnt);
      cyy = mpn_rshift (dy+1, s1, size, cnt);
#ifdef PRINT
      printf ("%*lX ", (int) (2 * sizeof(mp_limb_t)), cyx);
      mpn_print (dx+1, size);
      printf ("%*lX ", (int) (2 * sizeof(mp_limb_t)), cyy);
      mpn_print (dy+1, size);
#endif
      if (cyx != cyy || mpn_cmp (dx, dy, size+2) != 0
	  || dx[0] != 0x87654321 || dx[size+1] != 0x12345678)
	{
#ifndef PRINT
	  printf ("%*lX ", (int) (2 * sizeof(mp_limb_t)), cyx);
	  mpn_print (dx+1, size);
	  printf ("%*lX ", (int) (2 * sizeof(mp_limb_t)), cyy);
	  mpn_print (dy+1, size);
#endif
	  printf ("\n");
	  if (dy[0] != 0x87654321)
	    printf ("clobbered at low end\n");
	  if (dy[size+1] != 0x12345678)
	    printf ("clobbered at high end\n");
	  printf ("TEST NUMBER %u\n", test);
	  abort();
	}
#endif
    }
}

mpn_print (mp_ptr p, mp_size_t size)
{
  mp_size_t i;

  for (i = size - 1; i >= 0; i--)
    {
#ifdef _LONG_LONG_LIMB
      printf ("%0*lX%0*lX", (int) (sizeof(mp_limb_t)),
	      (unsigned long) (p[i] >> (BITS_PER_MP_LIMB/2)),
              (int) (sizeof(mp_limb_t)), (unsigned long) (p[i]));
#else
      printf ("%0*lX", (int) (2 * sizeof(mp_limb_t)), p[i]);
#endif
#ifdef SPACE
      if (i != 0)
	printf (" ");
#endif
    }
  puts ("");
}