glibc/sysdeps/ieee754/flt-32/s_lroundf.c

74 lines
1.8 KiB
C

/* Round float value to long int.
Copyright (C) 1997-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <limits.h>
#include <math.h>
#include <math_private.h>
#include <fix-fp-int-convert-overflow.h>
long int
__lroundf (float x)
{
int32_t j0;
u_int32_t i;
long int result;
int sign;
GET_FLOAT_WORD (i, x);
j0 = ((i >> 23) & 0xff) - 0x7f;
sign = (i & 0x80000000) != 0 ? -1 : 1;
i &= 0x7fffff;
i |= 0x800000;
if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
{
if (j0 < 0)
return j0 < -1 ? 0 : sign;
else if (j0 >= 23)
result = (long int) i << (j0 - 23);
else
{
i += 0x400000 >> j0;
result = i >> (23 - j0);
}
}
else
{
#ifdef FE_INVALID
/* The number is too large. Unless it rounds to LONG_MIN,
FE_INVALID must be raised and the return value is
unspecified. */
if (FIX_FLT_LONG_CONVERT_OVERFLOW && x != (float) LONG_MIN)
{
feraiseexcept (FE_INVALID);
return sign == 1 ? LONG_MAX : LONG_MIN;
}
#endif
return (long int) x;
}
return sign * result;
}
weak_alias (__lroundf, lroundf)