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  *  This program is free software; you can distribute it and/or modify it
   9  *  under the terms of the GNU General Public License (Version 2) as
  10  *  published by the Free Software Foundation.
  11  *
  12  *  This program is distributed in the hope it will be useful, but WITHOUT
  13  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  *  for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License along
  18  *  with this program; if not, write to the Free Software Foundation, Inc.,
  19  *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
  20  */
  21
  22 #include "ieee754sp.h"
  23 #include "ieee754dp.h"
  24
  25 union ieee754dp ieee754dp_fsp(union ieee754sp x)
  26 {
  27         COMPXSP;
  28
  29         EXPLODEXSP;
  30
  31         ieee754_clearcx();
  32
  33         FLUSHXSP;
  34
  35         switch (xc) {
  36         case IEEE754_CLASS_SNAN:
  37                 ieee754_setcx(IEEE754_INVALID_OPERATION);
  38                 return ieee754dp_nanxcpt(ieee754dp_indef());
  39
  40         case IEEE754_CLASS_QNAN:
  41                 return ieee754dp_nanxcpt(builddp(xs,
  42                                                  DP_EMAX + 1 + DP_EBIAS,
  43                                                  ((u64) xm
  44                                                   << (DP_FBITS -
  45                                                       SP_FBITS))));
  46         case IEEE754_CLASS_INF:
  47                 return ieee754dp_inf(xs);
  48
  49         case IEEE754_CLASS_ZERO:
  50                 return ieee754dp_zero(xs);
  51
  52         case IEEE754_CLASS_DNORM:
  53                 /* normalize */
  54                 while ((xm >> SP_FBITS) == 0) {
  55                         xm <<= 1;
  56                         xe--;
  57                 }
  58                 break;
  59
  60         case IEEE754_CLASS_NORM:
  61                 break;
  62         }
  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_FBITS - SP_FBITS));
  73 }