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

   1/* IEEE754 floating point arithmetic
   2 * double precision: common utilities
   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 "ieee754dp.h"
  29
  30ieee754dp ieee754dp_fsp(ieee754sp x)
  31{
  32        COMPXSP;
  33
  34        EXPLODEXSP;
  35
  36        CLEARCX;
  37
  38        FLUSHXSP;
  39
  40        switch (xc) {
  41        case IEEE754_CLASS_SNAN:
  42                SETCX(IEEE754_INVALID_OPERATION);
  43                return ieee754dp_nanxcpt(ieee754dp_indef(), "fsp");
  44        case IEEE754_CLASS_QNAN:
  45                return ieee754dp_nanxcpt(builddp(xs,
  46                                                 DP_EMAX + 1 + DP_EBIAS,
  47                                                 ((u64) xm
  48                                                  << (DP_MBITS -
  49                                                      SP_MBITS))), "fsp",
  50                                         x);
  51        case IEEE754_CLASS_INF:
  52                return ieee754dp_inf(xs);
  53        case IEEE754_CLASS_ZERO:
  54                return ieee754dp_zero(xs);
  55        case IEEE754_CLASS_DNORM:
  56                /* normalize */
  57                while ((xm >> SP_MBITS) == 0) {
  58                        xm <<= 1;
  59                        xe--;
  60                }
  61                break;
  62        case IEEE754_CLASS_NORM:
  63                break;
  64        }
  65
  66        /* CANT possibly overflow,underflow, or need rounding
  67         */
  68
  69        /* drop the hidden bit */
  70        xm &= ~SP_HIDDEN_BIT;
  71
  72        return builddp(xs, xe + DP_EBIAS,
  73                       (u64) xm << (DP_MBITS - SP_MBITS));
  74}
  75