arch/mips/math-emu/dp_fsp.c

   1 /* IEEE754 floating point arithmetic
   2  * double precision: common utilities
   3  */
   4 /*
   5  * MIPS floating point support
   6  * Copyright (C) 1994-2000 Algorithmics Ltd.  All rights reserved.
   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
  30 ieee754dp 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 }