lib/ldexpl.c

   1 /* Multiply a 'float' by a power of 2.
   2    Copyright 2002-2003, 2007-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file 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
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Paolo Bonzini and Bruno Haible.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include <math.h>
  23
  24 /* Avoid some warnings from "gcc -Wshadow".
  25    This file doesn't use the exp() function.  */
  26 #undef exp
  27 #define exp exponent
  28
  29 #if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
  30
  31 long double
  32 ldexpl (long double x, int exp)
  33 {
  34   return ldexp (x, exp);
  35 }
  36
  37 #else
  38
  39 # define USE_LONG_DOUBLE
  40 # include "ldexp.c"
  41
  42 #endif
  43
  44 #if 0
  45 int
  46 main (void)
  47 {
  48   long double x;
  49   int y;
  50   for (y = 0; y < 29; y++)
  51     printf ("%5d %.16Lg %.16Lg\n", y, ldexpl (0.8L, y), ldexpl (0.8L, -y) * ldexpl (0.8L, y));
  52 }
  53 #endif