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102 lines
4.2 KiB
C
102 lines
4.2 KiB
C
/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
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╚──────────────────────────────────────────────────────────────────────────────╝
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│ │
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│ Musl Libc │
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│ Copyright © 2005-2020 Rich Felker, et al. │
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│ │
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│ Permission is hereby granted, free of charge, to any person obtaining │
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│ a copy of this software and associated documentation files (the │
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│ "Software"), to deal in the Software without restriction, including │
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│ without limitation the rights to use, copy, modify, merge, publish, │
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│ distribute, sublicense, and/or sell copies of the Software, and to │
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│ permit persons to whom the Software is furnished to do so, subject to │
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│ the following conditions: │
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│ │
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│ The above copyright notice and this permission notice shall be │
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│ included in all copies or substantial portions of the Software. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
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│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
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│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
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│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
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│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
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│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
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│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/math.h"
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#include "libc/tinymath/complex.internal.h"
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#ifndef TINY
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asm(".ident\t\"\\n\\n\
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Musl libc (MIT License)\\n\
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Copyright 2005-2014 Rich Felker, et. al.\"");
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asm(".include \"libc/disclaimer.inc\"");
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/* clang-format off */
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/* origin: FreeBSD /usr/src/lib/msun/src/e_asinf.c */
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/*
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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static const double
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pio2 = 1.570796326794896558e+00;
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static const float
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/* coefficients for R(x^2) */
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pS0 = 1.6666586697e-01,
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pS1 = -4.2743422091e-02,
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pS2 = -8.6563630030e-03,
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qS1 = -7.0662963390e-01;
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static float R(float z)
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{
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float_t p, q;
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p = z*(pS0+z*(pS1+z*pS2));
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q = 1.0f+z*qS1;
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return p/q;
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}
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/**
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* Returns arc sine of 𝑥.
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*/
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float asinf(float x)
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{
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double s;
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float z;
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uint32_t hx,ix;
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GET_FLOAT_WORD(hx, x);
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ix = hx & 0x7fffffff;
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if (ix >= 0x3f800000) { /* |x| >= 1 */
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if (ix == 0x3f800000) /* |x| == 1 */
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return x*pio2 + 0x1p-120f; /* asin(+-1) = +-pi/2 with inexact */
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return 0/(x-x); /* asin(|x|>1) is NaN */
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}
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if (ix < 0x3f000000) { /* |x| < 0.5 */
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/* if 0x1p-126 <= |x| < 0x1p-12, avoid raising underflow */
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if (ix < 0x39800000 && ix >= 0x00800000)
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return x;
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return x + x*R(x*x);
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}
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/* 1 > |x| >= 0.5 */
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z = (1 - fabsf(x))*0.5f;
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s = sqrt(z);
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x = pio2 - 2*(s+s*R(z));
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if (hx >> 31)
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return -x;
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return x;
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}
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#endif /* TINY */
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