glibc/sysdeps/alpha/fpu/s_ceilf.c
Aurelien Jarno 062e53c195 alpha: fix ceil on sNaN input
The alpha version of ceil wrongly return sNaN for sNaN input. Fix that
by checking for NaN and by returning the input value added with itself
in that case.

Finally remove the code to handle inexact exception, ceil should never
generate such an exception.

Changelog:
	* sysdeps/alpha/fpu/s_ceil.c (__ceil): Add argument with itself
	when it is a NaN.
	[_IEEE_FP_INEXACT] Remove.
	* sysdeps/alpha/fpu/s_ceilf.c (__ceilf): Likewise.
2016-08-02 09:18:59 +02:00

54 lines
1.7 KiB
C

/* Copyright (C) 1998-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson.
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 <math.h>
/* Use the -inf rounding mode conversion instructions to implement
ceil, via something akin to -floor(-x). This is much faster than
playing with the fpcr to achieve +inf rounding mode. */
float
__ceilf (float x)
{
if (isnanf (x))
return x + x;
if (isless (fabsf (x), 16777216.0f)) /* 1 << FLT_MANT_DIG */
{
/* Note that Alpha S_Floating is stored in registers in a
restricted T_Floating format, so we don't even need to
convert back to S_Floating in the end. The initial
conversion to T_Floating is needed to handle denormals. */
float tmp1, tmp2, new_x;
new_x = -x;
__asm ("cvtst/s %3,%2\n\t"
"cvttq/svm %2,%1\n\t"
"cvtqt/m %1,%0\n\t"
: "=f"(new_x), "=&f"(tmp1), "=&f"(tmp2)
: "f"(new_x));
/* Fix up the negation we did above, as well as handling -0 properly. */
x = copysignf(new_x, x);
}
return x;
}
weak_alias (__ceilf, ceilf)