arch/mips/math-emu/dp_flong.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  * 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 "ieee754dp.h"
  29
  30 ieee754dp ieee754dp_flong(s64 x)
  31 {
  32         COMPXDP;
  33
  34         CLEARCX;
  35
  36         if (x == 0)
  37                 return ieee754dp_zero(0);
  38         if (x == 1 || x == -1)
  39                 return ieee754dp_one(x < 0);
  40         if (x == 10 || x == -10)
  41                 return ieee754dp_ten(x < 0);
  42
  43         xs = (x < 0);
  44         if (xs) {
  45                 if (x == (1ULL << 63))
  46                         xm = (1ULL << 63);      /* max neg can't be safely negated */
  47                 else
  48                         xm = -x;
  49         } else {
  50                 xm = x;
  51         }
  52
  53         /* normalize */
  54         xe = DP_MBITS + 3;
  55         if (xm >> (DP_MBITS + 1 + 3)) {
  56                 /* shunt out overflow bits */
  57                 while (xm >> (DP_MBITS + 1 + 3)) {
  58                         XDPSRSX1();
  59                 }
  60         } else {
  61                 /* normalize in grs extended double precision */
  62                 while ((xm >> (DP_MBITS + 3)) == 0) {
  63                         xm <<= 1;
  64                         xe--;
  65                 }
  66         }
  67         DPNORMRET1(xs, xe, xm, "dp_flong", x);
  68 }
  69
  70 ieee754dp ieee754dp_fulong(u64 u)
  71 {
  72         if ((s64) u < 0)
  73                 return ieee754dp_add(ieee754dp_1e63(),
  74                                      ieee754dp_flong(u & ~(1ULL << 63)));
  75         return ieee754dp_flong(u);
  76 }