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.
   7  *
   8  * ########################################################################
   9  *
  10  *  This program is free software; you can distribute it and/or modify it
  11  *  under the terms of the GNU General Public License (Version 2) as
  12  *  published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope it will be useful, but WITHOUT
  15  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17  *  for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License along
  20  *  with this program; if not, write to the Free Software Foundation, Inc.,
  21  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * ########################################################################
  24  */
  25
  26
  27 #include "ieee754dp.h"
  28
  29 ieee754dp ieee754dp_fsp(ieee754sp x)
  30 {
  31         COMPXSP;
  32
  33         EXPLODEXSP;
  34
  35         CLEARCX;
  36
  37         FLUSHXSP;
  38
  39         switch (xc) {
  40         case IEEE754_CLASS_SNAN:
  41                 SETCX(IEEE754_INVALID_OPERATION);
  42                 return ieee754dp_nanxcpt(ieee754dp_indef(), "fsp");
  43         case IEEE754_CLASS_QNAN:
  44                 return ieee754dp_nanxcpt(builddp(xs,
  45                                                  DP_EMAX + 1 + DP_EBIAS,
  46                                                  ((u64) xm
  47                                                   << (DP_MBITS -
  48                                                       SP_MBITS))), "fsp",
  49                                          x);
  50         case IEEE754_CLASS_INF:
  51                 return ieee754dp_inf(xs);
  52         case IEEE754_CLASS_ZERO:
  53                 return ieee754dp_zero(xs);
  54         case IEEE754_CLASS_DNORM:
  55                 /* normalize */
  56                 while ((xm >> SP_MBITS) == 0) {
  57                         xm <<= 1;
  58                         xe--;
  59                 }
  60                 break;
  61         case IEEE754_CLASS_NORM:
  62                 break;
  63         }
  64
  65         /* CAN'T possibly overflow,underflow, or need rounding
  66          */
  67
  68         /* drop the hidden bit */
  69         xm &= ~SP_HIDDEN_BIT;
  70
  71         return builddp(xs, xe + DP_EBIAS,
  72                        (u64) xm << (DP_MBITS - SP_MBITS));
  73 }