glibc/sysdeps/ieee754/dbl-64/s_totalorder.c
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54 lines
1.8 KiB
C

/* Total order operation. dbl-64 version.
Copyright (C) 2016-2018 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
<http://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <libm-alias-double.h>
#include <nan-high-order-bit.h>
#include <stdint.h>
int
__totalorder (double x, double y)
{
int32_t hx, hy;
uint32_t lx, ly;
EXTRACT_WORDS (hx, lx, x);
EXTRACT_WORDS (hy, ly, y);
#if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
uint32_t uhx = hx & 0x7fffffff, uhy = hy & 0x7fffffff;
/* For the preferred quiet NaN convention, this operation is a
comparison of the representations of the arguments interpreted as
sign-magnitude integers. If both arguments are NaNs, invert the
quiet/signaling bit so comparing that way works. */
if ((uhx > 0x7ff00000 || (uhx == 0x7ff00000 && lx != 0))
&& (uhy > 0x7ff00000 || (uhy == 0x7ff00000 && ly != 0)))
{
hx ^= 0x00080000;
hy ^= 0x00080000;
}
#endif
uint32_t hx_sign = hx >> 31;
uint32_t hy_sign = hy >> 31;
hx ^= hx_sign >> 1;
lx ^= hx_sign;
hy ^= hy_sign >> 1;
ly ^= hy_sign;
return hx < hy || (hx == hy && lx <= ly);
}
libm_alias_double (__totalorder, totalorder)