Back to index

glibc  2.9
s_llroundf.c
Go to the documentation of this file.
00001 /* Round float value to long long int.
00002    Copyright (C) 1997 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
00005 
00006    The GNU C Library is free software; you can redistribute it and/or
00007    modify it under the terms of the GNU Lesser General Public
00008    License as published by the Free Software Foundation; either
00009    version 2.1 of the License, or (at your option) any later version.
00010 
00011    The GNU C Library is distributed in the hope that it will be useful,
00012    but WITHOUT ANY WARRANTY; without even the implied warranty of
00013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014    Lesser General Public License for more details.
00015 
00016    You should have received a copy of the GNU Lesser General Public
00017    License along with the GNU C Library; if not, write to the Free
00018    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00019    02111-1307 USA.  */
00020 
00021 #include <math.h>
00022 
00023 #include "math_private.h"
00024 
00025 
00026 long long int
00027 __llroundf (float x)
00028 {
00029   int32_t j0;
00030   u_int32_t i;
00031   long long int result;
00032   int sign;
00033 
00034   GET_FLOAT_WORD (i, x);
00035   j0 = ((i >> 23) & 0xff) - 0x7f;
00036   sign = (i & 0x80000000) != 0 ? -1 : 1;
00037   i &= 0x7fffff;
00038   i |= 0x800000;
00039 
00040   if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
00041     {
00042       if (j0 < 0)
00043        return j0 < -1 ? 0 : sign;
00044       else if (j0 >= 23)
00045        result = (long long int) i << (j0 - 23);
00046       else
00047        {
00048          i += 0x400000 >> j0;
00049 
00050          result = i >> (23 - j0);
00051        }
00052     }
00053   else
00054     {
00055       /* The number is too large.  It is left implementation defined
00056         what happens.  */
00057       return (long long int) x;
00058     }
00059 
00060   return sign * result;
00061 }
00062 
00063 weak_alias (__llroundf, llroundf)