circuitpython/lib/libm/kf_sin.c

59 lines
1.6 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* These math functions are taken from newlib-nano-2, the newlib/libm/math
* directory, available from https://github.com/32bitmicro/newlib-nano-2.
*
* Appropriate copyright headers are reproduced below.
*/
/* kf_sin.c -- float version of k_sin.c
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "fdlibm.h"
#ifdef __STDC__
static const float
#else
static float
#endif
half = 5.0000000000e-01f,/* 0x3f000000 */
S1 = -1.6666667163e-01f, /* 0xbe2aaaab */
S2 = 8.3333337680e-03f, /* 0x3c088889 */
S3 = -1.9841270114e-04f, /* 0xb9500d01 */
S4 = 2.7557314297e-06f, /* 0x3638ef1b */
S5 = -2.5050759689e-08f, /* 0xb2d72f34 */
S6 = 1.5896910177e-10f; /* 0x2f2ec9d3 */
#ifdef __STDC__
float __kernel_sinf(float x, float y, int iy)
#else
float __kernel_sinf(x, y, iy)
float x,y; int iy; /* iy=0 if y is zero */
#endif
{
float z,r,v;
__int32_t ix;
GET_FLOAT_WORD(ix,x);
ix &= 0x7fffffff; /* high word of x */
if(ix<0x32000000) /* |x| < 2**-27 */
{if((int)x==0) return x;} /* generate inexact */
z = x*x;
v = z*x;
r = S2+z*(S3+z*(S4+z*(S5+z*S6)));
if(iy==0) return x+v*(S1+z*r);
else return x-((z*(half*y-v*r)-y)-v*S1);
}