//===========================================================================
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//===========================================================================
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//
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//
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// s_sin.c
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// s_sin.c
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//
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//
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// Part of the standard mathematical function library
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// Part of the standard mathematical function library
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//
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//
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//===========================================================================
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//===========================================================================
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//####ECOSGPLCOPYRIGHTBEGIN####
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//####ECOSGPLCOPYRIGHTBEGIN####
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// -------------------------------------------
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// -------------------------------------------
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// This file is part of eCos, the Embedded Configurable Operating System.
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// This file is part of eCos, the Embedded Configurable Operating System.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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//
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//
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// eCos is free software; you can redistribute it and/or modify it under
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// eCos is free software; you can redistribute it and/or modify it under
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// the terms of the GNU General Public License as published by the Free
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// the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 or (at your option) any later version.
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// Software Foundation; either version 2 or (at your option) any later version.
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//
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//
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// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
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// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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// for more details.
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//
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//
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// You should have received a copy of the GNU General Public License along
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// You should have received a copy of the GNU General Public License along
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// with eCos; if not, write to the Free Software Foundation, Inc.,
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// with eCos; if not, write to the Free Software Foundation, Inc.,
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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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//
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//
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// As a special exception, if other files instantiate templates or use macros
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// As a special exception, if other files instantiate templates or use macros
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// or inline functions from this file, or you compile this file and link it
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// or inline functions from this file, or you compile this file and link it
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// with other works to produce a work based on this file, this file does not
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// with other works to produce a work based on this file, this file does not
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// by itself cause the resulting work to be covered by the GNU General Public
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// by itself cause the resulting work to be covered by the GNU General Public
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// License. However the source code for this file must still be made available
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// License. However the source code for this file must still be made available
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// in accordance with section (3) of the GNU General Public License.
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// in accordance with section (3) of the GNU General Public License.
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//
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//
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// This exception does not invalidate any other reasons why a work based on
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// This exception does not invalidate any other reasons why a work based on
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// this file might be covered by the GNU General Public License.
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// this file might be covered by the GNU General Public License.
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//
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//
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// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
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// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
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// at http://sources.redhat.com/ecos/ecos-license/
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// at http://sources.redhat.com/ecos/ecos-license/
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// -------------------------------------------
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// -------------------------------------------
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//####ECOSGPLCOPYRIGHTEND####
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//####ECOSGPLCOPYRIGHTEND####
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//===========================================================================
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//===========================================================================
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//#####DESCRIPTIONBEGIN####
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//#####DESCRIPTIONBEGIN####
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//
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//
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// Author(s): jlarmour
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// Author(s): jlarmour
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// Contributors: jlarmour
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// Contributors: jlarmour
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// Date: 1998-02-13
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// Date: 1998-02-13
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// Purpose:
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// Purpose:
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// Description:
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// Description:
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// Usage:
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// Usage:
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//
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//
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//####DESCRIPTIONEND####
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//####DESCRIPTIONEND####
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//
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//
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//===========================================================================
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//===========================================================================
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// CONFIGURATION
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// CONFIGURATION
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#include <pkgconf/libm.h> // Configuration header
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#include <pkgconf/libm.h> // Configuration header
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// Include the Math library?
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// Include the Math library?
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#ifdef CYGPKG_LIBM
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#ifdef CYGPKG_LIBM
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// Derived from code with the following copyright
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// Derived from code with the following copyright
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/* @(#)s_sin.c 1.3 95/01/18 */
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/* @(#)s_sin.c 1.3 95/01/18 */
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/*
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/*
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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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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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*
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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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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* software is freely granted, provided that this notice
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* is preserved.
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* is preserved.
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* ====================================================
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* ====================================================
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*/
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*/
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/* sin(x)
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/* sin(x)
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* Return sine function of x.
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* Return sine function of x.
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*
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*
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* kernel function:
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* kernel function:
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* __kernel_sin ... sine function on [-pi/4,pi/4]
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* __kernel_sin ... sine function on [-pi/4,pi/4]
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* __kernel_cos ... cose function on [-pi/4,pi/4]
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* __kernel_cos ... cose function on [-pi/4,pi/4]
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* __ieee754_rem_pio2 ... argument reduction routine
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* __ieee754_rem_pio2 ... argument reduction routine
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*
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*
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* Method.
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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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* 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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* [-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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* in [-pi/4 , +pi/4], and let n = k mod 4.
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* We have
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* We have
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*
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*
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* n sin(x) cos(x) tan(x)
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* n sin(x) cos(x) tan(x)
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* ----------------------------------------------------------
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* ----------------------------------------------------------
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* 0 S C T
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* 0 S C T
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* 1 C -S -1/T
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* 1 C -S -1/T
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* 2 -S -C T
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* 2 -S -C T
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* 3 -C S -1/T
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* 3 -C S -1/T
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* ----------------------------------------------------------
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* ----------------------------------------------------------
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*
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*
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* Special cases:
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* Special cases:
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* Let trig be any of sin, cos, or tan.
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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(+-INF) is NaN, with signals;
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* trig(NaN) is that NaN;
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* trig(NaN) is that NaN;
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*
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*
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* Accuracy:
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* Accuracy:
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* TRIG(x) returns trig(x) nearly rounded
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* TRIG(x) returns trig(x) nearly rounded
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*/
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*/
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#include "mathincl/fdlibm.h"
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#include "mathincl/fdlibm.h"
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double sin(double x)
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double sin(double x)
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{
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{
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double y[2],z=0.0;
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double y[2],z=0.0;
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int n, ix;
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int n, ix;
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/* High word of x. */
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/* High word of x. */
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ix = CYG_LIBM_HI(x);
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ix = CYG_LIBM_HI(x);
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/* |x| ~< pi/4 */
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/* |x| ~< pi/4 */
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ix &= 0x7fffffff;
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ix &= 0x7fffffff;
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if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0);
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if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0);
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/* sin(Inf or NaN) is NaN */
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/* sin(Inf or NaN) is NaN */
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else if (ix>=0x7ff00000) return x-x;
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else if (ix>=0x7ff00000) return x-x;
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/* argument reduction needed */
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/* argument reduction needed */
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else {
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else {
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n = __ieee754_rem_pio2(x,y);
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n = __ieee754_rem_pio2(x,y);
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switch(n&3) {
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switch(n&3) {
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case 0: return __kernel_sin(y[0],y[1],1);
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case 0: return __kernel_sin(y[0],y[1],1);
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case 1: return __kernel_cos(y[0],y[1]);
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case 1: return __kernel_cos(y[0],y[1]);
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case 2: return -__kernel_sin(y[0],y[1],1);
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case 2: return -__kernel_sin(y[0],y[1],1);
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default:
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default:
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return -__kernel_cos(y[0],y[1]);
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return -__kernel_cos(y[0],y[1]);
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}
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}
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}
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}
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}
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}
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#endif // ifdef CYGPKG_LIBM
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#endif // ifdef CYGPKG_LIBM
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// EOF s_sin.c
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// EOF s_sin.c
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