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/* Copyright (C) 2007-2017 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 chopped rounding mode conversion instructions to implement trunc. */
double
__trunc (double x)
{
double two52 = copysign (0x1.0p52, x);
double r, tmp;
if (isgreaterequal (fabs (x), 0x1.0p52))
return x;
__asm (
"addt/suc %2, %3, %1\n\tsubt/suc %1, %3, %0"
: "=&f"(r), "=&f"(tmp)
: "f"(x), "f"(two52));
/* trunc(-0) == -0, and in general we'll always have the same
sign as our input. */
return copysign (r, x);
}
weak_alias (__trunc, trunc)
#ifdef NO_LONG_DOUBLE
strong_alias (__trunc, __truncl)
weak_alias (__trunc, truncl)
#endif
#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
compat_symbol (libm, __trunc, truncl, GLIBC_2_1);
#endif
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