arch/mips/math-emu/sp_fdp.c

   1 /* IEEE754 floating point arithmetic
   2  * single precision
   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 "ieee754sp.h"
  28
  29 ieee754sp ieee754sp_fdp(ieee754dp x)
  30 {
  31         COMPXDP;
  32         ieee754sp nan;
  33
  34         EXPLODEXDP;
  35
  36         CLEARCX;
  37
  38         FLUSHXDP;
  39
  40         switch (xc) {
  41         case IEEE754_CLASS_SNAN:
  42                 SETCX(IEEE754_INVALID_OPERATION);
  43                 return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp");
  44         case IEEE754_CLASS_QNAN:
  45                 nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32)
  46                                 (xm >> (DP_MBITS - SP_MBITS)));
  47                 if (!ieee754sp_isnan(nan))
  48                         nan = ieee754sp_indef();
  49                 return ieee754sp_nanxcpt(nan, "fdp", x);
  50         case IEEE754_CLASS_INF:
  51                 return ieee754sp_inf(xs);
  52         case IEEE754_CLASS_ZERO:
  53                 return ieee754sp_zero(xs);
  54         case IEEE754_CLASS_DNORM:
  55                 /* can't possibly be sp representable */
  56                 SETCX(IEEE754_UNDERFLOW);
  57                 SETCX(IEEE754_INEXACT);
  58                 if ((ieee754_csr.rm == IEEE754_RU && !xs) ||
  59                                 (ieee754_csr.rm == IEEE754_RD && xs))
  60                         return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x);
  61                 return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x);
  62         case IEEE754_CLASS_NORM:
  63                 break;
  64         }
  65
  66         {
  67                 u32 rm;
  68
  69                 /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift
  70                  */
  71                 rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) |
  72                     ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0);
  73
  74                 SPNORMRET1(xs, xe, rm, "fdp", x);
  75         }
  76 }