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2fc507c98f
* modelines: tw -> sw shiftwidth, not textwidth. * space-surround modelines * fix irregular modelines * Fix modeline in titlegen.c
111 lines
5.4 KiB
C
111 lines
5.4 KiB
C
/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8 :vi │
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╚──────────────────────────────────────────────────────────────────────────────╝
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│ │
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│ FreeBSD lib/msun/src/e_acoshl.c │
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│ Converted to ldbl by David Schultz <das@FreeBSD.ORG> and Bruce D. Evans. │
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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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│ Copyright (c) 1992-2023 The FreeBSD Project. │
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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, this list of conditions and the following 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 AND CONTRIBUTORS ``AS IS'' AND │
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│ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE │
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│ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE │
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│ ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE │
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│ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL │
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│ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS │
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│ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) │
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│ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT │
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│ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY │
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│ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF │
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│ SUCH DAMAGE. │
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/math.h"
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#include "libc/tinymath/freebsd.internal.h"
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#if !(LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024)
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asm(".ident\t\"\\n\\n\
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FreeBSD libm (BSD-2 License)\\n\
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Copyright (c) 2005-2011, Bruce D. Evans, Steven G. Kargl, David Schultz.\"");
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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(".include \"libc/disclaimer.inc\"");
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// clang-format off
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/* EXP_LARGE is the threshold above which we use acosh(x) ~= log(2x). */
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#if LDBL_MANT_DIG == 64
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#define EXP_LARGE 34
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#elif LDBL_MANT_DIG == 113
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#define EXP_LARGE 58
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#else
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#error "Unsupported long double format"
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#endif
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#if LDBL_MAX_EXP != 0x4000
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/* We also require the usual expsign encoding. */
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#error "Unsupported long double format"
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#endif
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static const double
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one = 1.0;
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#if LDBL_MANT_DIG == 64
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static const union IEEEl2bits
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u_ln2 = LD80C(0xb17217f7d1cf79ac, -1, 6.93147180559945309417e-1L);
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#define ln2 u_ln2.e
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#elif LDBL_MANT_DIG == 113
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static const long double
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ln2 = 6.93147180559945309417232121458176568e-1L; /* 0x162e42fefa39ef35793c7673007e6.0p-113 */
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#else
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#error "Unsupported long double format"
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#endif
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/**
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* Returns inverse hyperbolic cosine of 𝑥.
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* @define acosh(x) = log(x + sqrt(x*x-1))
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*/
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long double
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acoshl(long double x)
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{
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long double t;
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int16_t hx;
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ENTERI();
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GET_LDBL_EXPSIGN(hx, x);
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if (hx < 0x3fff) { /* x < 1, or misnormal */
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RETURNI((x-x)/(x-x));
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} else if (hx >= BIAS + EXP_LARGE) { /* x >= LARGE */
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if (hx >= 0x7fff) { /* x is inf, NaN or misnormal */
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RETURNI(x+x);
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} else {
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RETURNI(logl(x)+ln2); /* acosh(huge)=log(2x), or misnormal */
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}
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} else if (hx == 0x3fff && x == 1) {
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RETURNI(0.0); /* acosh(1) = 0 */
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} else if (hx >= 0x4000) { /* LARGE > x >= 2, or misnormal */
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t=x*x;
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RETURNI(logl(2.0*x-one/(x+sqrtl(t-one))));
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} else { /* 1<x<2 */
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t = x-one;
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RETURNI(log1pl(t+sqrtl(2.0*t+t*t)));
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}
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}
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#endif /* long double is long */
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