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 * 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
  30ieee754sp 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}
  78