111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/*-
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* Copyright (c) 2017-2023 Steven G. Kargl
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* See ../src/s_sinpi.c for implementation details.
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*/
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#include "math.h"
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#include "math_private.h"
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/*
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* pi_hi contains the leading 56 bits of a 169 bit approximation for pi.
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*/
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static const long double
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pi_hi = 3.14159265358979322702026593105983920e+00L,
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pi_lo = 1.14423774522196636802434264184180742e-17L;
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#include "k_cospil.h"
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#include "k_sinpil.h"
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static volatile const double vzero = 0;
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long double
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sinpil(long double x)
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{
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long double ai, ar, ax, hi, lo, s;
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ax = fabsl(x);
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if (ax < 1) {
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if (ax < 0.25) {
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if (ax < 0x1p-60) {
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if (x == 0)
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return (x);
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hi = (double)x;
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hi *= 0x1p113L;
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lo = x * 0x1p113L - hi;
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s = (pi_lo + pi_hi) * lo + pi_lo * lo +
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pi_hi * hi;
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return (s * 0x1p-113L);
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}
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s = __kernel_sinpil(ax);
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return (x < 0 ? -s : s);
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}
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if (ax < 0.5)
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s = __kernel_cospil(0.5 - ax);
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else if (ax < 0.75)
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s = __kernel_cospil(ax - 0.5);
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else
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s = __kernel_sinpil(1 - ax);
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return (x < 0 ? -s : s);
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}
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if (ax < 0x1p112) {
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/* Split ax = ai + ar with 0 <= ar < 1. */
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FFLOORL128(ax, ai, ar);
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if (ar == 0) {
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s = 0;
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} else {
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if (ar < 0.5) {
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if (ar <= 0.25)
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s = __kernel_sinpil(ar);
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else
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s = __kernel_cospil(0.5 - ar);
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} else {
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if (ar < 0.75)
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s = __kernel_cospil(ar - 0.5);
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else
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s = __kernel_sinpil(1 - ar);
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}
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s = fmodl(ai, 2.L) == 0 ? s : -s;
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}
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return (x < 0 ? -s : s);
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}
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if (isinf(x) || isnan(x))
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return (vzero / vzero);
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/*
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* |x| >= 0x1p112 is always an integer, so return +-0.
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*/
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return (copysignl(0, x));
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}
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