mirror of
https://github.com/jart/cosmopolitan.git
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121 lines
4.9 KiB
C
121 lines
4.9 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 © 2005-2014 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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#include "libc/tinymath/feval.internal.h"
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#include "libc/tinymath/kernel.internal.h"
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asm(".ident\t\"\\n\\n\
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fdlibm (fdlibm license)\\n\
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Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.\"");
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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/s_cosf.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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* Optimized by Bruce D. Evans.
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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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/* Small multiples of pi/2 rounded to double precision. */
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static const double
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c1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
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c2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
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c3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
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c4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
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/**
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* Returns cosine of 𝑥.
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* @note should take about 5ns
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*/
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float cosf(float x)
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{
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double y;
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uint32_t ix;
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unsigned n, sign;
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GET_FLOAT_WORD(ix, x);
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sign = ix >> 31;
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ix &= 0x7fffffff;
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if (ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
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if (ix < 0x39800000) { /* |x| < 2**-12 */
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/* raise inexact if x != 0 */
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FORCE_EVAL(x + 0x1p120f);
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return 1.0f;
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}
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return __cosdf(x);
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}
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if (ix <= 0x407b53d1) { /* |x| ~<= 5*pi/4 */
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if (ix > 0x4016cbe3) /* |x| ~> 3*pi/4 */
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return -__cosdf(sign ? x+c2pio2 : x-c2pio2);
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else {
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if (sign)
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return __sindf(x + c1pio2);
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else
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return __sindf(c1pio2 - x);
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}
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}
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if (ix <= 0x40e231d5) { /* |x| ~<= 9*pi/4 */
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if (ix > 0x40afeddf) /* |x| ~> 7*pi/4 */
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return __cosdf(sign ? x+c4pio2 : x-c4pio2);
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else {
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if (sign)
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return __sindf(-x - c3pio2);
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else
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return __sindf(x - c3pio2);
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}
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}
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/* cos(Inf or NaN) is NaN */
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if (ix >= 0x7f800000)
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return x-x;
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/* general argument reduction needed */
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n = __rem_pio2f(x,&y);
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switch (n&3) {
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case 0: return __cosdf(y);
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case 1: return __sindf(-y);
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case 2: return -__cosdf(y);
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default:
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return __sindf(y);
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}
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}
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