Mercurial > nand-ecoscentric
diff packages/language/c/libm/current/src/float/internal/kf_tan.c @ 3337:77f9d3253c3e
Add: Complex number header and library (single and double precision floating point),
port from Newlib.
Add: Single precision floating point library, port from Newlib.
[ Bugzilla 1001539 ]
| author | vae |
|---|---|
| date | Sun, 25 Aug 2013 14:38:57 +0000 |
| parents | |
| children |
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new file mode 100644 --- /dev/null +++ b/packages/language/c/libm/current/src/float/internal/kf_tan.c @@ -0,0 +1,163 @@ +//=========================================================================== +// +// kf_tan.c +// +// Part of the standard mathematical function library +// +//=========================================================================== +// ####ECOSGPLCOPYRIGHTBEGIN#### +// ------------------------------------------- +// This file is part of eCos, the Embedded Configurable Operating System. +// Copyright (C) 2012 Free Software Foundation, Inc. +// +// eCos is free software; you can redistribute it and/or modify it under +// the terms of the GNU General Public License as published by the Free +// Software Foundation; either version 2 or (at your option) any later +// version. +// +// eCos is distributed in the hope that it will be useful, but WITHOUT +// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +// for more details. +// +// You should have received a copy of the GNU General Public License +// along with eCos; if not, write to the Free Software Foundation, Inc., +// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +// +// As a special exception, if other files instantiate templates or use +// macros or inline functions from this file, or you compile this file +// and link it with other works to produce a work based on this file, +// this file does not by itself cause the resulting work to be covered by +// the GNU General Public License. However the source code for this file +// must still be made available in accordance with section (3) of the GNU +// General Public License v2. +// +// This exception does not invalidate any other reasons why a work based +// on this file might be covered by the GNU General Public License. +// ------------------------------------------- +// ####ECOSGPLCOPYRIGHTEND#### +//=========================================================================== +//#####DESCRIPTIONBEGIN#### +// +// Author(s): +// Contributors: visar, ilijak +// Date: 2012-03-08 +// Purpose: +// Description: +// Usage: +// +//####DESCRIPTIONEND#### +// +//=========================================================================== + +// CONFIGURATION + +#include <pkgconf/libm.h> // Configuration header + +// Include the Math library? +#ifdef CYGPKG_LIBM + +// Derived from code with the following copyright + + +/* kf_tan.c -- float version of k_tan.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 "mathincl/fdlibm.h" +#ifdef __STDC__ +static const float +#else +static float +#endif +one = 1.0000000000e+00, /* 0x3f800000 */ +pio4 = 7.8539812565e-01, /* 0x3f490fda */ +pio4lo= 3.7748947079e-08, /* 0x33222168 */ +T[] = { + 3.3333334327e-01, /* 0x3eaaaaab */ + 1.3333334029e-01, /* 0x3e088889 */ + 5.3968254477e-02, /* 0x3d5d0dd1 */ + 2.1869488060e-02, /* 0x3cb327a4 */ + 8.8632395491e-03, /* 0x3c11371f */ + 3.5920790397e-03, /* 0x3b6b6916 */ + 1.4562094584e-03, /* 0x3abede48 */ + 5.8804126456e-04, /* 0x3a1a26c8 */ + 2.4646313977e-04, /* 0x398137b9 */ + 7.8179444245e-05, /* 0x38a3f445 */ + 7.1407252108e-05, /* 0x3895c07a */ + -1.8558637748e-05, /* 0xb79bae5f */ + 2.5907305826e-05, /* 0x37d95384 */ +}; + +#ifdef __STDC__ + float __kernel_tanf(float x, float y, int iy) +#else + float __kernel_tanf(x, y, iy) + float x,y; int iy; +#endif +{ + float z,r,v,w,s; + __int32_t ix,hx; + hx = CYG_LIBM_WORD(x); + ix = hx&0x7fffffff; /* high word of |x| */ + if(ix<0x31800000) /* x < 2**-28 */ + {if((int)x==0) { /* generate inexact */ + if((ix|(iy+1))==0) return one/fabsf(x); + else return (iy==1)? x: -one/x; + } + } + if(ix>=0x3f2ca140) { /* |x|>=0.6744 */ + if(hx<0) {x = -x; y = -y;} + z = pio4-x; + w = pio4lo-y; + x = z+w; y = 0.0; + } + z = x*x; + w = z*z; + /* Break x^5*(T[1]+x^2*T[2]+...) into + * x^5(T[1]+x^4*T[3]+...+x^20*T[11]) + + * x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12])) + */ + r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11])))); + v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12]))))); + s = z*x; + r = y + z*(s*(r+v)+y); + r += T[0]*s; + w = x+r; + if(ix>=0x3f2ca140) { + v = (float)iy; + return (float)(1-((hx>>30)&2))*(v-(float)2.0*(x-(w*w/(w+v)-r))); + } + if(iy==1) return w; + else { /* if allow error up to 2 ulp, + simply return -1.0/(x+r) here */ + /* compute -1.0/(x+r) accurately */ + float a,t; + __int32_t i; + z = w; + i = CYG_LIBM_WORD(z); + SET_FLOAT_WORD(z,i&0xfffff000); + v = r-(z - x); /* z+v = r+x */ + t = a = -(float)1.0/w; /* a = -1.0/w */ + i = CYG_LIBM_WORD(t); + SET_FLOAT_WORD(t,i&0xfffff000); + s = (float)1.0+t*z; + return t+a*(s+t*v); + } +} + +#endif // ifdef CYGPKG_LIBM + +// EOF kf_tan.c
