mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
99 lines
5 KiB
C
99 lines
5 KiB
C
/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
|
|
╚──────────────────────────────────────────────────────────────────────────────╝
|
|
│ │
|
|
│ Musl Libc │
|
|
│ Copyright © 2005-2014 Rich Felker, et al. │
|
|
│ │
|
|
│ Permission is hereby granted, free of charge, to any person obtaining │
|
|
│ a copy of this software and associated documentation files (the │
|
|
│ "Software"), to deal in the Software without restriction, including │
|
|
│ without limitation the rights to use, copy, modify, merge, publish, │
|
|
│ distribute, sublicense, and/or sell copies of the Software, and to │
|
|
│ permit persons to whom the Software is furnished to do so, subject to │
|
|
│ the following conditions: │
|
|
│ │
|
|
│ The above copyright notice and this permission notice shall be │
|
|
│ included in all copies or substantial portions of the Software. │
|
|
│ │
|
|
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
|
|
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
|
|
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
|
|
│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
|
|
│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
|
|
│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
|
|
│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
|
|
│ │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "libc/math.h"
|
|
#include "libc/tinymath/kernel.internal.h"
|
|
|
|
asm(".ident\t\"\\n\\n\
|
|
fdlibm (fdlibm license)\\n\
|
|
Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.\"");
|
|
asm(".ident\t\"\\n\\n\
|
|
Musl libc (MIT License)\\n\
|
|
Copyright 2005-2014 Rich Felker, et. al.\"");
|
|
asm(".include \"libc/disclaimer.inc\"");
|
|
|
|
/* clang-format off */
|
|
/* origin: FreeBSD /usr/src/lib/msun/src/k_sin.c */
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunSoft, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
* ====================================================
|
|
*/
|
|
/* __sin( x, y, iy)
|
|
* kernel sin function on ~[-pi/4, pi/4] (except on -0), pi/4 ~ 0.7854
|
|
* Input x is assumed to be bounded by ~pi/4 in magnitude.
|
|
* Input y is the tail of x.
|
|
* Input iy indicates whether y is 0. (if iy=0, y assume to be 0).
|
|
*
|
|
* Algorithm
|
|
* 1. Since sin(-x) = -sin(x), we need only to consider positive x.
|
|
* 2. Callers must return sin(-0) = -0 without calling here since our
|
|
* odd polynomial is not evaluated in a way that preserves -0.
|
|
* Callers may do the optimization sin(x) ~ x for tiny x.
|
|
* 3. sin(x) is approximated by a polynomial of degree 13 on
|
|
* [0,pi/4]
|
|
* 3 13
|
|
* sin(x) ~ x + S1*x + ... + S6*x
|
|
* where
|
|
*
|
|
* |sin(x) 2 4 6 8 10 12 | -58
|
|
* |----- - (1+S1*x +S2*x +S3*x +S4*x +S5*x +S6*x )| <= 2
|
|
* | x |
|
|
*
|
|
* 4. sin(x+y) = sin(x) + sin'(x')*y
|
|
* ~ sin(x) + (1-x*x/2)*y
|
|
* For better accuracy, let
|
|
* 3 2 2 2 2
|
|
* r = x *(S2+x *(S3+x *(S4+x *(S5+x *S6))))
|
|
* then 3 2
|
|
* sin(x) = x + (S1*x + (x *(r-y/2)+y))
|
|
*/
|
|
|
|
#define S1 -1.66666666666666324348e-01
|
|
#define S2 8.33333333332248946124e-03
|
|
#define S3 -1.98412698298579493134e-04
|
|
#define S4 2.75573137070700676789e-06
|
|
#define S5 -2.50507602534068634195e-08
|
|
#define S6 1.58969099521155010221e-10
|
|
|
|
double __sin(double x, double y, int iy)
|
|
{
|
|
double_t z,r,v,w;
|
|
z = x*x;
|
|
w = z*z;
|
|
r = S2 + z*(S3 + z*S4) + z*w*(S5 + z*S6);
|
|
v = z*x;
|
|
if (iy == 0)
|
|
return x + v*(S1 + z*r);
|
|
else
|
|
return x - ((z*(0.5*y - v*r) - y) - v*S1);
|
|
}
|