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  * 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 "ieee754sp.h"
  29
  30 ieee754sp ieee754sp_fdp(ieee754dp x)
  31 {
  32         COMPXDP;
  33         ieee754sp nan;
  34
  35         EXPLODEXDP;
  36
  37         CLEARCX;
  38
  39         FLUSHXDP;
  40
  41         switch (xc) {
  42         case IEEE754_CLASS_SNAN:
  43                 SETCX(IEEE754_INVALID_OPERATION);
  44                 return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp");
  45         case IEEE754_CLASS_QNAN:
  46                 nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32)
  47                                 (xm >> (DP_MBITS - SP_MBITS)));
  48                 if (!ieee754sp_isnan(nan))
  49                         nan = ieee754sp_indef();
  50                 return ieee754sp_nanxcpt(nan, "fdp", x);
  51         case IEEE754_CLASS_INF:
  52                 return ieee754sp_inf(xs);
  53         case IEEE754_CLASS_ZERO:
  54                 return ieee754sp_zero(xs);
  55         case IEEE754_CLASS_DNORM:
  56                 /* can't possibly be sp representable */
  57                 SETCX(IEEE754_UNDERFLOW);
  58                 SETCX(IEEE754_INEXACT);
  59                 if ((ieee754_csr.rm == IEEE754_RU && !xs) ||
  60                                 (ieee754_csr.rm == IEEE754_RD && xs))
  61                         return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x);
  62                 return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x);
  63         case IEEE754_CLASS_NORM:
  64                 break;
  65         }
  66
  67         {
  68                 u32 rm;
  69
  70                 /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift
  71                  */
  72                 rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) |
  73                     ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0);
  74
  75                 SPNORMRET1(xs, xe, rm, "fdp", x);
  76         }
  77 }