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git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14719 87f5fb63-7c3d-0410-a384-fd976d0f7a62
137 lines
4.2 KiB
C
Executable File
137 lines
4.2 KiB
C
Executable File
/*
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* $Id: math_rint.c,v 1.3 2004-08-27 13:49:17 obarthel Exp $
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*
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* :ts=4
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*
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* Portable ISO 'C' (1994) runtime library for the Amiga computer
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* Copyright (c) 2002-2004 by Olaf Barthel <olsen@sourcery.han.de>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Neither the name of Olaf Barthel nor the names of contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*
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* PowerPC math library based in part on work by Sun Microsystems
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, 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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#ifndef _MATH_HEADERS_H
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#include "math_headers.h"
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#endif /* _MATH_HEADERS_H */
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/****************************************************************************/
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/* The following is not part of the ISO 'C' (1994) (1994) standard. */
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/****************************************************************************/
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#if defined(FLOATING_POINT_SUPPORT)
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/****************************************************************************/
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#if defined(IEEE_FLOATING_POINT_SUPPORT) || defined(M68881_FLOATING_POINT_SUPPORT)
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/****************************************************************************/
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double
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rint(double x)
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{
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return floor ( x+0.5 );
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}
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/****************************************************************************/
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#endif /* IEEE_FLOATING_POINT_SUPPORT || M68881_FLOATING_POINT_SUPPORT */
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/****************************************************************************/
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#if defined(PPC_FLOATING_POINT_SUPPORT)
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/****************************************************************************/
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static const double
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TWO52[2]={
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4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
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-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
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};
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double
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rint(double x)
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{
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int i0,j0,sx;
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unsigned i,i1;
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double w,t;
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GET_HIGH_WORD(i0,x);
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sx = (i0>>31)&1;
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GET_LOW_WORD(i1,x);
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j0 = ((i0>>20)&0x7ff)-0x3ff;
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if(j0<20) {
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if(j0<0) {
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if(((i0&0x7fffffff)|i1)==0) return x;
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i1 |= (i0&0x0fffff);
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i0 &= 0xfffe0000;
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i0 |= ((i1|-i1)>>12)&0x80000;
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SET_HIGH_WORD(x,i0);
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w = TWO52[sx]+x;
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t = w-TWO52[sx];
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GET_HIGH_WORD(i0,t);
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SET_HIGH_WORD(t,(i0&0x7fffffff)|(sx<<31));
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return t;
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} else {
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i = (0x000fffff)>>j0;
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if(((i0&i)|i1)==0) return x; /* x is integral */
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i>>=1;
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if(((i0&i)|i1)!=0) {
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if(j0==19) i1 = 0x40000000; else
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i0 = (i0&(~i))|((0x20000)>>j0);
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}
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}
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} else if (j0>51) {
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if(j0==0x400) return x+x; /* inf or NaN */
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else return x; /* x is integral */
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} else {
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i = ((unsigned)(0xffffffff))>>(j0-20);
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if((i1&i)==0) return x; /* x is integral */
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i>>=1;
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if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));
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}
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SET_HIGH_WORD(x,i0);
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SET_LOW_WORD(x,i1);
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w = TWO52[sx]+x;
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return w-TWO52[sx];
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}
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/****************************************************************************/
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#endif /* PPC_FLOATING_POINT_SUPPORT */
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/****************************************************************************/
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#endif /* FLOATING_POINT_SUPPORT */
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