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/* Round to integer type. ldbl-96 version.
Copyright (C) 2016-2022 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/>. */
#include <errno.h>
#include <fenv.h>
#include <math.h>
#include <math_private.h>
#include <libm-alias-ldouble.h>
#include <stdbool.h>
#include <stdint.h>
#define BIAS 0x3fff
#define MANT_DIG 64
#if UNSIGNED
# define RET_TYPE uintmax_t
#else
# define RET_TYPE intmax_t
#endif
#include <fromfp.h>
RET_TYPE
FUNC (long double x, int round, unsigned int width)
{
if (width > INTMAX_WIDTH)
width = INTMAX_WIDTH;
uint16_t se;
uint32_t hx, lx;
GET_LDOUBLE_WORDS (se, hx, lx, x);
bool negative = (se & 0x8000) != 0;
if (width == 0)
return fromfp_domain_error (negative, width);
if ((hx | lx) == 0)
return 0;
int exponent = se & 0x7fff;
exponent -= BIAS;
int max_exponent = fromfp_max_exponent (negative, width);
if (exponent > max_exponent)
return fromfp_domain_error (negative, width);
uint64_t ix = (((uint64_t) hx) << 32) | lx;
uintmax_t uret;
bool half_bit, more_bits;
if (exponent >= MANT_DIG - 1)
{
uret = ix;
/* Exponent 63; no shifting required. */
half_bit = false;
more_bits = false;
}
else if (exponent >= -1)
{
uint64_t h = 1ULL << (MANT_DIG - 2 - exponent);
half_bit = (ix & h) != 0;
more_bits = (ix & (h - 1)) != 0;
if (exponent == -1)
uret = 0;
else
uret = ix >> (MANT_DIG - 1 - exponent);
}
else
{
uret = 0;
half_bit = false;
more_bits = true;
}
return fromfp_round_and_return (negative, uret, half_bit, more_bits, round,
exponent, max_exponent, width);
}
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