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/* Copyright (C) 1998-2018 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>
#include <math_ldbl_opt.h>
#include <libm-alias-double.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. */
double
__ceil (double x)
{
if (isnan (x))
return x + x;
if (isless (fabs (x), 9007199254740992.0)) /* 1 << DBL_MANT_DIG */
{
double tmp1, new_x;
new_x = -x;
__asm (
"cvttq/svm %2,%1\n\t"
"cvtqt/m %1,%0\n\t"
: "=f"(new_x), "=&f"(tmp1)
: "f"(new_x));
/* Fix up the negation we did above, as well as handling -0 properly. */
x = copysign(new_x, x);
}
return x;
}
libm_alias_double (__ceil, ceil)
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