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//===========================================================================
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//
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// s_modf.c
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//
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// Part of the standard mathematical function library
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//
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//===========================================================================
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//####ECOSGPLCOPYRIGHTBEGIN####
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// -------------------------------------------
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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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//
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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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// Software Foundation; either version 2 or (at your option) any later version.
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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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// 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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// for more details.
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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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// 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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//
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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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// 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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// 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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//
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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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//
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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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// -------------------------------------------
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//####ECOSGPLCOPYRIGHTEND####
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//===========================================================================
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//#####DESCRIPTIONBEGIN####
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//
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// Author(s): jlarmour
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// Contributors: jlarmour
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// Date: 1998-02-13
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// Purpose:
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// Description:
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// Usage:
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//
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//####DESCRIPTIONEND####
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//
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//===========================================================================
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// CONFIGURATION
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#include <pkgconf/libm.h> // Configuration header
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// Include the Math library?
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#ifdef CYGPKG_LIBM
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// Derived from code with the following copyright
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/* @(#)s_modf.c 1.3 95/01/18 */
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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 SunSoft, 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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/*
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* modf(double x, double *iptr)
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* return fraction part of x, and return x's integral part in *iptr.
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* Method:
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* Bit twiddling.
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*
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* Exception:
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* No exception.
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*/
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#include "mathincl/fdlibm.h"
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static const double one = 1.0;
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double modf(double x, double *iptr)
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{
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int i0,i1,j0;
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unsigned i;
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i0 = CYG_LIBM_HI(x); /* high x */
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i1 = CYG_LIBM_LO(x); /* low x */
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j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */
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if(j0<20) { /* integer part in high x */
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if(j0<0) { /* |x|<1 */
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CYG_LIBM_HIp(iptr) = i0&0x80000000;
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CYG_LIBM_LOp(iptr) = 0; /* *iptr = +-0 */
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return x;
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} else {
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i = (0x000fffff)>>j0;
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if(((i0&i)|i1)==0) { /* x is integral */
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*iptr = x;
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CYG_LIBM_HI(x) &= 0x80000000;
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CYG_LIBM_LO(x) = 0; /* return +-0 */
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return x;
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} else {
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CYG_LIBM_HIp(iptr) = i0&(~i);
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CYG_LIBM_LOp(iptr) = 0;
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return x - *iptr;
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}
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}
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} else if (j0>51) { /* no fraction part */
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*iptr = x*one;
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CYG_LIBM_HI(x) &= 0x80000000;
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CYG_LIBM_LO(x) = 0; /* return +-0 */
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return x;
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} else { /* fraction part in low x */
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i = ((unsigned)(0xffffffff))>>(j0-20);
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if((i1&i)==0) { /* x is integral */
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*iptr = x;
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CYG_LIBM_HI(x) &= 0x80000000;
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CYG_LIBM_LO(x) = 0; /* return +-0 */
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return x;
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} else {
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CYG_LIBM_HIp(iptr) = i0;
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CYG_LIBM_LOp(iptr) = i1&(~i);
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return x - *iptr;
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}
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}
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}
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#endif // ifdef CYGPKG_LIBM
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// EOF s_modf.c
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