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128 lines
3.0 KiB
C
128 lines
3.0 KiB
C
/* Copyright (C) 1997-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#include <math.h>
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#include <math_private.h>
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#include "mathimpl.h"
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#include <libm-alias-finite.h>
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#ifndef SUFF
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#define SUFF
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#endif
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#ifndef float_type
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#define float_type double
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#endif
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#define CONCATX(a,b) __CONCAT(a,b)
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#define s(name) CONCATX(name,SUFF)
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#define m81(func) __m81_u(s(func))
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float_type
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s(__ieee754_pow) (float_type x, float_type y)
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{
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float_type z;
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float_type ax;
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unsigned long x_cond, y_cond;
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y_cond = __m81_test (y);
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if (y_cond & __M81_COND_ZERO)
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return 1.0;
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if (y_cond & __M81_COND_NAN)
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return x == 1.0 ? x : x + y;
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x_cond = __m81_test (x);
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if (x_cond & __M81_COND_NAN)
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return x + y;
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if (y_cond & __M81_COND_INF)
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{
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ax = s(fabs) (x);
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if (ax == 1.0)
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return ax;
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if (ax > 1.0)
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return y_cond & __M81_COND_NEG ? 0 : y;
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else
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return y_cond & __M81_COND_NEG ? -y : 0;
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}
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if (s(fabs) (y) == 1.0)
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return y_cond & __M81_COND_NEG ? 1 / x : x;
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if (y == 2)
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return x * x;
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if (y == 0.5 && !(x_cond & __M81_COND_NEG))
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return m81(sqrt) (x);
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if (x == 10.0)
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{
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__asm ("ftentox%.x %1, %0" : "=f" (z) : "f" (y));
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return z;
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}
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if (x == 2.0)
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{
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__asm ("ftwotox%.x %1, %0" : "=f" (z) : "f" (y));
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return z;
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}
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ax = s(fabs) (x);
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if (x_cond & (__M81_COND_INF | __M81_COND_ZERO) || ax == 1.0)
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{
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z = ax;
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if (y_cond & __M81_COND_NEG)
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z = 1 / z;
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if (x_cond & __M81_COND_NEG)
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{
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if (y != m81(__rint) (y))
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{
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if (x == -1)
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z = (z - z) / (z - z);
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}
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else
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goto maybe_negate;
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}
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return z;
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}
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if (x_cond & __M81_COND_NEG)
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{
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if (y == m81(__rint) (y))
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{
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z = m81(__ieee754_exp) (y * m81(__ieee754_log) (-x));
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maybe_negate:
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/* We always use the long double format, since y is already in
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this format and rounding won't change the result. */
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{
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int32_t exponent;
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uint32_t i0, i1;
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GET_LDOUBLE_WORDS (exponent, i0, i1, y);
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exponent = (exponent & 0x7fff) - 0x3fff;
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if (exponent <= 31
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? i0 & (1 << (31 - exponent))
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: (exponent <= 63
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&& i1 & (1 << (63 - exponent))))
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z = -z;
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}
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}
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else
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z = (y - y) / (y - y);
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}
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else
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z = m81(__ieee754_exp) (y * m81(__ieee754_log) (x));
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return z;
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}
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libm_alias_finite (s(__ieee754_pow), s (__pow))
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