sysdeps/powerpc/q_stoq.c

   1 /* 32-bit floating point to 128-bit floating point.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <quad_float.h>
  21
  22 /* long double _q_stoq(float a);
  23    Convert 'a' to long double. Don't raise exceptions.
  24    */
  25
  26 void
  27 __q_stoq(unsigned long long result[2], float a)
  28 {
  29   unsigned ux, rx;
  30   union {
  31     float d;
  32     unsigned u;
  33   } u;
  34
  35   u.d = a;
  36   result[1] = 0;
  37   result[0] = u.u << 32-7;
  38   /* correct exponent bias */
  39   rx = ((int)u.u >> 23 & 0x80ff) + 16383-127;
  40
  41   ux = u.u >> 23 & 0xff;
  42   if (ux == 0)
  43     {
  44       if ((u.u & 0x7fffffff) == 0)
  45         {
  46           /* +0.0 or -0.0.  */
  47           rx &= 0x8000;
  48         }
  49       else
  50         {
  51           /* Denormalised number.  Renormalise.  */
  52           unsigned um = u.u & 0x007fffff;
  53           int cs = cntlzw(um) - 9 + 1;
  54           rx -= cs;
  55           um <<= cs;
  56           result[0] = um << 32-7;
  57         }
  58     }
  59   else if (ux == 0xff)
  60     {
  61       /* Inf or NaN.  */
  62       rx |= 0x7fff;
  63     }
  64   *(unsigned short *)result = rx;
  65 }