ports/sysdeps/m68k/m680x0/fpu/e_ilogb.c

   1 /* Copyright (C) 1996-2014 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <math.h>
  19 #include "mathimpl.h"
  20
  21 #ifndef SUFF
  22 #define SUFF
  23 #endif
  24 #ifndef float_type
  25 #define float_type double
  26 #endif
  27
  28 #define CONCATX(a,b) __CONCAT(a,b)
  29 #define s(name) CONCATX(name,SUFF)
  30 #define m81(func) __m81_u(s(func))
  31
  32 int
  33 s(__ieee754_ilogb) (float_type x)
  34 {
  35   float_type result;
  36   unsigned long x_cond;
  37
  38   x_cond = __m81_test (x);
  39   /* We must return consistent values for zero and NaN.  */
  40   if (x_cond & __M81_COND_ZERO)
  41     return FP_ILOGB0;
  42   if (x_cond & (__M81_COND_NAN | __M81_COND_INF))
  43     return FP_ILOGBNAN;
  44
  45   __asm ("fgetexp%.x %1, %0" : "=f" (result) : "f" (x));
  46   return (int) result;
  47 }