mirror of
https://github.com/jart/cosmopolitan.git
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592f6ebc20
- Write some more unit tests - memcpy() on ARM is now faster - Address the Musl complex math FIXME comments - Some libm funcs like pow() now support setting errno - Import the latest and greatest math functions from ARM - Use more accurate atan2f() and log1pf() implementations - atoi() and atol() will no longer saturate or clobber errno
113 lines
4.8 KiB
C
113 lines
4.8 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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│ 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/feval.internal.h"
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#include "libc/tinymath/kernel.internal.h"
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__static_yoink("musl_libc_notice");
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__static_yoink("fdlibm_notice");
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/* origin: FreeBSD /usr/src/lib/msun/src/s_tan.c */
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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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#define asuint64(f) ((union{double _f; uint64_t _i;}){f})._i
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#define gethighw(hi,d) (hi) = asuint64(d) >> 32
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/* tan(x)
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* Return tangent function of x.
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*
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* kernel function:
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* __tan ... tangent function on [-pi/4,pi/4]
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* __rem_pio2 ... argument reduction routine
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*
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* Method.
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* Let S,C and T denote the sin, cos and tan respectively on
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* [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
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* in [-pi/4 , +pi/4], and let n = k mod 4.
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* We have
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*
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* n sin(x) cos(x) tan(x)
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* ----------------------------------------------------------
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* 0 S C T
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* 1 C -S -1/T
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* 2 -S -C T
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* 3 -C S -1/T
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* ----------------------------------------------------------
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*
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* Special cases:
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* Let trig be any of sin, cos, or tan.
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* trig(+-INF) is NaN, with signals;
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* trig(NaN) is that NaN;
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*
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* Accuracy:
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* TRIG(x) returns trig(x) nearly rounded
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*/
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/**
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* Returns tangent of x.
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*/
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double tan(double x)
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{
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double y[2];
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uint32_t ix;
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unsigned n;
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gethighw(ix, x);
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ix &= 0x7fffffff;
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/* |x| ~< pi/4 */
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if (ix <= 0x3fe921fb) {
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if (ix < 0x3e400000) { /* |x| < 2**-27 */
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/* raise inexact if x!=0 and underflow if subnormal */
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feval(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f);
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return x;
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}
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return __tan(x, 0.0, 0);
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}
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/* tan(Inf or NaN) is NaN */
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if (ix >= 0x7ff00000)
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return x - x;
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/* argument reduction */
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n = __rem_pio2(x, y);
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return __tan(y[0], y[1], n&1);
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}
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#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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__weak_reference(tan, tanl);
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#endif
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