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/*
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright © 2021 Keith Packard
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "stdio_private.h"
#include <float.h>
#if __LDBL_MAX_10_EXP__ >= 4096
#define NPOW_10 13
#elif __LDBL_MAX_10_EXP__ >= 2048
#define NPOW_10 12
#elif __LDBL_MAX_10_EXP__ >= 1024
#define NPOW_10 11
#elif __LDBL_MAX_10_EXP__ >= 512
#define NPOW_10 10
#elif __LDBL_MAX_10_EXP__ >= 256
#define NPOW_10 9
#elif __LDBL_MAX_10_EXP__ >= 128
#define NPOW_10 8
#elif __LDBL_MAX_10_EXP__ >= 64
#define NPOW_10 7
#elif __LDBL_MAX_10_EXP__ >= 32
#define NPOW_10 6
#else
#error __LDBL_MAX_10_EXP__ too small
#endif
static const long double pwr_p10[NPOW_10] = { 1e+1L, 1e+2L, 1e+4L, 1e+8L, 1e+16L, 1e+32L,
#if NPOW_10 >= 7
1e+64L,
#endif
#if NPOW_10 >= 8
1e+128L,
#endif
#if NPOW_10 >= 9
1e+256L,
#endif
#if NPOW_10 >= 10
1e+512L,
#endif
#if NPOW_10 >= 11
1e+1024L,
#endif
#if NPOW_10 >= 12
1e+2048L,
#endif
#if NPOW_10 >= 13
1e+4096L
#endif
};
static const long double pwr_m10[NPOW_10] = { 1e-1L, 1e-2L, 1e-4L, 1e-8L, 1e-16L, 1e-32L,
#if NPOW_10 >= 7
1e-64L,
#endif
#if NPOW_10 >= 8
1e-128L,
#endif
#if NPOW_10 >= 9
1e-256L,
#endif
#if NPOW_10 >= 10
1e-512L,
#endif
#if NPOW_10 >= 11
1e-1024L,
#endif
#if NPOW_10 >= 12
1e-2048L,
#endif
#if NPOW_10 >= 13
1e-4096L
#endif
};
long double
__atold_engine(_u128 m10, int e10)
{
long double flt = _u128_to_ld(m10);
int pwr;
const long double *pptr;
if (e10 < 0) {
pptr = (pwr_m10 + NPOW_10 - 1);
e10 = -e10;
} else {
pptr = (pwr_p10 + NPOW_10 - 1);
}
for (pwr = 1 << (NPOW_10 - 1); pwr; pwr >>= 1) {
for (; e10 >= pwr; e10 -= pwr) {
flt *= *pptr;
}
pptr--;
}
return flt;
}
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