sysdeps/m68k/m680x0/fpu/s_frexp_template.c

   1 /* Implement frexp for m68k.
   2    Copyright (C) 1996-2021 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20
  21 FLOAT
  22 M_DECL_FUNC (__frexp) (FLOAT value, int *expptr)
  23 {
  24   FLOAT mantissa, exponent;
  25   int iexponent;
  26   unsigned long fpsr;
  27
  28   __asm ("ftst%.x %1\n"
  29          "fmove%.l %/fpsr, %0"
  30          : "=dm" (fpsr) : "f" (value));
  31   if (fpsr & (7 << 24))
  32     {
  33       /* Not finite or zero.  */
  34       *expptr = 0;
  35       return value;
  36     }
  37   __asm ("fgetexp%.x %1, %0" : "=f" (exponent) : "f" (value));
  38   iexponent = (int) exponent + 1;
  39   *expptr = iexponent;
  40   __asm ("fscale%.l %2, %0"
  41          : "=f" (mantissa)
  42          : "0" (value), "dmi" (-iexponent));
  43   return mantissa;
  44 }
  45 declare_mgen_alias (__frexp, frexp)