mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-12 06:10:10 +00:00
91 lines
2.5 KiB
C
91 lines
2.5 KiB
C
/* Round to integer type. ldbl-128 version.
|
|
Copyright (C) 2016-2017 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 <errno.h>
|
|
#include <fenv.h>
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
|
|
#define BIAS 0x3fff
|
|
#define MANT_DIG 113
|
|
|
|
#if UNSIGNED
|
|
# define RET_TYPE uintmax_t
|
|
#else
|
|
# define RET_TYPE intmax_t
|
|
#endif
|
|
|
|
#include <fromfp.h>
|
|
|
|
RET_TYPE
|
|
FUNC (_Float128 x, int round, unsigned int width)
|
|
{
|
|
if (width > INTMAX_WIDTH)
|
|
width = INTMAX_WIDTH;
|
|
uint64_t hx, lx;
|
|
GET_LDOUBLE_WORDS64 (hx, lx, x);
|
|
bool negative = (hx & 0x8000000000000000ULL) != 0;
|
|
if (width == 0)
|
|
return fromfp_domain_error (negative, width);
|
|
hx &= 0x7fffffffffffffffULL;
|
|
if ((hx | lx) == 0)
|
|
return 0;
|
|
int exponent = hx >> (MANT_DIG - 1 - 64);
|
|
exponent -= BIAS;
|
|
int max_exponent = fromfp_max_exponent (negative, width);
|
|
if (exponent > max_exponent)
|
|
return fromfp_domain_error (negative, width);
|
|
|
|
hx &= ((1ULL << (MANT_DIG - 1 - 64)) - 1);
|
|
hx |= 1ULL << (MANT_DIG - 1 - 64);
|
|
uintmax_t uret;
|
|
bool half_bit, more_bits;
|
|
/* The exponent is at most 63, so we are shifting right by at least
|
|
49 bits. */
|
|
if (exponent >= -1)
|
|
{
|
|
int shift = MANT_DIG - 1 - exponent;
|
|
if (shift <= 64)
|
|
{
|
|
uint64_t h = 1ULL << (shift - 1);
|
|
half_bit = (lx & h) != 0;
|
|
more_bits = (lx & (h - 1)) != 0;
|
|
uret = hx << (64 - shift);
|
|
if (shift != 64)
|
|
uret |= lx >> shift;
|
|
}
|
|
else
|
|
{
|
|
uint64_t h = 1ULL << (shift - 1 - 64);
|
|
half_bit = (hx & h) != 0;
|
|
more_bits = ((hx & (h - 1)) | lx) != 0;
|
|
uret = hx >> (shift - 64);
|
|
}
|
|
}
|
|
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);
|
|
}
|