glibc/sysdeps/ieee754/flt-32/s_roundf.c
Ulrich Drepper abfbdde177 Update.
1999-07-14 00:54:57 +00:00

74 lines
1.7 KiB
C

/* Round float to integer away from zero.
Copyright (C) 1997 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <math.h>
#include "math_private.h"
static const float huge = 1.0e30;
float
__roundf (float x)
{
int32_t i0, j0;
GET_FLOAT_WORD (i0, x);
j0 = ((i0 >> 23) & 0xff) - 0x7f;
if (j0 < 23)
{
if (j0 < 0)
{
if (huge + x > 0.0F)
{
i0 &= 0x80000000;
if (j0 == -1)
i0 |= 0x3f800000;
}
}
else
{
u_int32_t i = 0x007fffff >> j0;
if ((i0 & i) == 0)
/* X is integral. */
return x;
if (huge + x > 0.0F)
{
/* Raise inexact if x != 0. */
i0 += 0x00400000 >> j0;
i0 &= ~i;
}
}
}
else
{
if (j0 == 0x80)
/* Inf or NaN. */
return x + x;
else
return x;
}
SET_FLOAT_WORD (x, i0);
return x;
}
weak_alias (__roundf, roundf)