LXR linux/arch/mips/math-emu/sp

   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
  29ieee754sp 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}
  77