glibc/sysdeps/ieee754/flt-32/s_setpayloadf_main.c

55 lines
1.8 KiB
C

/* Set NaN payload. flt-32 version.
Copyright (C) 2016-2020 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 <math.h>
#include <math_private.h>
#include <libm-alias-float.h>
#include <nan-high-order-bit.h>
#include <stdint.h>
#define SET_HIGH_BIT (HIGH_ORDER_BIT_IS_SET_FOR_SNAN ? SIG : !SIG)
#define BIAS 0x7f
#define PAYLOAD_DIG 22
#define EXPLICIT_MANT_DIG 23
int
FUNC (float *x, float payload)
{
uint32_t ix;
GET_FLOAT_WORD (ix, payload);
int exponent = ix >> EXPLICIT_MANT_DIG;
/* Test if argument is (a) negative or too large; (b) too small,
except for 0 when allowed; (c) not an integer. */
if (exponent >= BIAS + PAYLOAD_DIG
|| (exponent < BIAS && !(SET_HIGH_BIT && ix == 0))
|| (ix & ((1U << (BIAS + EXPLICIT_MANT_DIG - exponent)) - 1)) != 0)
{
SET_FLOAT_WORD (*x, 0);
return 1;
}
if (ix != 0)
{
ix &= (1U << EXPLICIT_MANT_DIG) - 1;
ix |= 1U << EXPLICIT_MANT_DIG;
ix >>= BIAS + EXPLICIT_MANT_DIG - exponent;
}
ix |= 0x7f800000 | (SET_HIGH_BIT ? 0x400000 : 0);
SET_FLOAT_WORD (*x, ix);
return 0;
}