mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-03 04:01:43 +08:00
61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
/* Truncate argument to nearest integral value not larger than the argument.
|
|
Copyright (C) 1997-2024 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#define NO_MATH_REDIRECT
|
|
#include <math.h>
|
|
|
|
#include <math_private.h>
|
|
#include <libm-alias-double.h>
|
|
#include <math-use-builtins.h>
|
|
|
|
|
|
double
|
|
__trunc (double x)
|
|
{
|
|
#if USE_TRUNC_BUILTIN
|
|
return __builtin_trunc (x);
|
|
#else
|
|
/* Use generic implementation. */
|
|
int64_t i0, j0;
|
|
int64_t sx;
|
|
|
|
EXTRACT_WORDS64 (i0, x);
|
|
sx = i0 & UINT64_C (0x8000000000000000);
|
|
j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
|
|
if (j0 < 52)
|
|
{
|
|
if (j0 < 0)
|
|
/* The magnitude of the number is < 1 so the result is +-0. */
|
|
INSERT_WORDS64 (x, sx);
|
|
else
|
|
INSERT_WORDS64 (x, sx | (i0 & ~(UINT64_C (0x000fffffffffffff) >> j0)));
|
|
}
|
|
else
|
|
{
|
|
if (j0 == 0x400)
|
|
/* x is inf or NaN. */
|
|
return x + x;
|
|
}
|
|
|
|
return x;
|
|
#endif /* ! USE_TRUNC_BUILTIN */
|
|
}
|
|
#ifndef __trunc
|
|
libm_alias_double (__trunc, trunc)
|
|
#endif
|