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/* Copyright (C) 1998-2017 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>
/* Use the -inf rounding mode conversion instructions to implement
floor. We note when the exponent is large enough that the value
must be integral, as this avoids unpleasant integer overflows. */
double
__floor (double x)
{
if (isnan (x))
return x + x;
if (isless (fabs (x), 9007199254740992.0)) /* 1 << DBL_MANT_DIG */
{
double tmp1, new_x;
__asm (
"cvttq/svm %2,%1\n\t"
"cvtqt/m %1,%0\n\t"
: "=f"(new_x), "=&f"(tmp1)
: "f"(x));
/* floor(-0) == -0, and in general we'll always have the same
sign as our input. */
x = copysign(new_x, x);
}
return x;
}
weak_alias (__floor, floor)
#ifdef NO_LONG_DOUBLE
strong_alias (__floor, __floorl)
weak_alias (__floor, floorl)
#endif
#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
compat_symbol (libm, __floor, floorl, GLIBC_2_0);
#endif
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