Subversion Repositories openrisc

/* Copyright (C) 2004, 2006, 2009 Free Software Foundation, Inc.

This file is free software; you can redistribute it and/or modify it

under the terms of the GNU General Public License as published by the

Free Software Foundation; either version 3, or (at your option) any

later version.

This file 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

General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional

permissions described in the GCC Runtime Library Exception, version

3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and

a copy of the GCC Runtime Library Exception along with this program;

see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

<http://www.gnu.org/licenses/>.  */

/* Calculate division table for ST40-300 integer division

   Contributed by Joern Rennecke

   joern.rennecke@st.com  */

#include <stdio.h>

#include <math.h>

int

main ()

{

  int i, j;

  double q, r, err, max_err = 0, max_s_err = 0;

  puts("/* This table has been generated by divtab-sh4.c.  */");

  puts ("\t.balign 4");

  for (i = -128; i < 128; i++)

    {

      int n = 0;

      if (i == 0)

        {

          /* output some dummy number for 1/0.  */

          puts ("LOCAL(div_table_clz):\n\t.byte\t0");

          continue;

        }

      for (j = i < 0 ? -i : i; j < 128; j += j)

        n++;

      printf ("\t.byte\t%d\n", n - 7);

    }

  puts("\

/* 1/-128 .. 1/127, normalized.  There is an implicit leading 1 in bit 32,\n\

   or in bit 33 for powers of two.  */\n\

        .balign 4");

  for (i = -128; i < 128; i++)

    {

      if (i == 0)

        {

          puts ("LOCAL(div_table_inv):\n\t.long\t0x0");

          continue;

        }

      j = i < 0 ? -i : i;

      while (j < 64)

        j += j;

      q = 4.*(1<<30)*128/j;

      r = ceil (q);

      printf ("\t.long\t0x%X\n", (unsigned) r);

      err = r - q;

      if (err > max_err)

        max_err = err;

      err = err * j / 128;

      if (err > max_s_err)

        max_s_err = err;

    }

  printf ("\t/* maximum error: %f scaled: %f*/\n", max_err, max_s_err);

  exit (0);

}