sysdeps/m68k/fpu/s_frexp.c

   1 /* Copyright (C) 1996, 1997, 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <math.h>
  20
  21 #ifndef FUNC
  22 #define FUNC frexp
  23 #endif
  24 #ifndef float_type
  25 #define float_type double
  26 #endif
  27
  28 #define __CONCATX(a,b) __CONCAT(a,b)
  29
  30 float_type
  31 __CONCATX(__,FUNC) (float_type value, int *expptr)
  32 {
  33   float_type mantissa, exponent;
  34   int iexponent;
  35   unsigned long fpsr;
  36
  37   __asm ("ftst%.x %1\n"
  38          "fmove%.l %/fpsr, %0"
  39          : "=dm" (fpsr) : "f" (value));
  40   if (fpsr & (7 << 24))
  41     {
  42       /* Not finite or zero.  */
  43       *expptr = 0;
  44       return value;
  45     }
  46   __asm ("fgetexp%.x %1, %0" : "=f" (exponent) : "f" (value));
  47   iexponent = (int) exponent + 1;
  48   *expptr = iexponent;
  49   __asm ("fscale%.l %2, %0"
  50          : "=f" (mantissa)
  51          : "0" (value), "dmi" (-iexponent));
  52   return mantissa;
  53 }
  54
  55 #define weak_aliasx(a,b) weak_alias(a,b)
  56 weak_aliasx (__CONCATX(__,FUNC), FUNC)