LXR linux/arch/mips/math-emu/sp

   1/* IEEE754 floating point arithmetic
   2 * single precision
   3 */
   4/*
   5 * MIPS floating point support
   6 * Copyright (C) 1994-2000 Algorithmics Ltd.
   7 * http://www.algor.co.uk
   8 *
   9 * ########################################################################
  10 *
  11 *  This program is free software; you can distribute it and/or modify it
  12 *  under the terms of the GNU General Public License (Version 2) as
  13 *  published by the Free Software Foundation.
  14 *
  15 *  This program is distributed in the hope it will be useful, but WITHOUT
  16 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18 *  for more details.
  19 *
  20 *  You should have received a copy of the GNU General Public License along
  21 *  with this program; if not, write to the Free Software Foundation, Inc.,
  22 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  23 *
  24 * ########################################################################
  25 */
  26
  27
  28#include "ieee754sp.h"
  29
  30ieee754sp ieee754sp_fint(int x)
  31{
  32        unsigned xm;
  33        int xe;
  34        int xs;
  35
  36        CLEARCX;
  37
  38        if (x == 0)
  39                return ieee754sp_zero(0);
  40        if (x == 1 || x == -1)
  41                return ieee754sp_one(x < 0);
  42        if (x == 10 || x == -10)
  43                return ieee754sp_ten(x < 0);
  44
  45        xs = (x < 0);
  46        if (xs) {
  47                if (x == (1 << 31))
  48                        xm = ((unsigned) 1 << 31);      /* max neg can't be safely negated */
  49                else
  50                        xm = -x;
  51        } else {
  52                xm = x;
  53        }
  54        xe = SP_MBITS + 3;
  55
  56        if (xm >> (SP_MBITS + 1 + 3)) {
  57                /* shunt out overflow bits
  58                 */
  59                while (xm >> (SP_MBITS + 1 + 3)) {
  60                        SPXSRSX1();
  61                }
  62        } else {
  63                /* normalize in grs extended single precision
  64                 */
  65                while ((xm >> (SP_MBITS + 3)) == 0) {
  66                        xm <<= 1;
  67                        xe--;
  68                }
  69        }
  70        SPNORMRET1(xs, xe, xm, "fint", x);
  71}
  72
  73
  74ieee754sp ieee754sp_funs(unsigned int u)
  75{
  76        if ((int) u < 0)
  77                return ieee754sp_add(ieee754sp_1e31(),
  78                                     ieee754sp_fint(u & ~(1 << 31)));
  79        return ieee754sp_fint(u);
  80}
  81