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glibc  2.9
s_truncf.c
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00001 /* Truncate argument to nearest integral value not larger than the argument.
00002    Copyright (C) 1997, 1998 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 float
00027 __truncf (float x)
00028 {
00029   int32_t i0, j0;
00030   int sx;
00031 
00032   GET_FLOAT_WORD (i0, x);
00033   sx = i0 & 0x80000000;
00034   j0 = ((i0 >> 23) & 0xff) - 0x7f;
00035   if (j0 < 23)
00036     {
00037       if (j0 < 0)
00038        /* The magnitude of the number is < 1 so the result is +-0.  */
00039        SET_FLOAT_WORD (x, sx);
00040       else
00041        SET_FLOAT_WORD (x, sx | (i0 & ~(0x007fffff >> j0)));
00042     }
00043   else
00044     {
00045       if (j0 == 0x80)
00046        /* x is inf or NaN.  */
00047        return x + x;
00048     }
00049 
00050   return x;
00051 }
00052 weak_alias (__truncf, truncf)