1 //===========================================================================
5 // Part of the standard mathematical function library
7 //===========================================================================
8 //####ECOSGPLCOPYRIGHTBEGIN####
9 // -------------------------------------------
10 // This file is part of eCos, the Embedded Configurable Operating System.
11 // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
13 // eCos is free software; you can redistribute it and/or modify it under
14 // the terms of the GNU General Public License as published by the Free
15 // Software Foundation; either version 2 or (at your option) any later version.
17 // eCos is distributed in the hope that it will be useful, but WITHOUT ANY
18 // WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
22 // You should have received a copy of the GNU General Public License along
23 // with eCos; if not, write to the Free Software Foundation, Inc.,
24 // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
26 // As a special exception, if other files instantiate templates or use macros
27 // or inline functions from this file, or you compile this file and link it
28 // with other works to produce a work based on this file, this file does not
29 // by itself cause the resulting work to be covered by the GNU General Public
30 // License. However the source code for this file must still be made available
31 // in accordance with section (3) of the GNU General Public License.
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34 // this file might be covered by the GNU General Public License.
36 // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
37 // at http://sources.redhat.com/ecos/ecos-license/
38 // -------------------------------------------
39 //####ECOSGPLCOPYRIGHTEND####
40 //===========================================================================
41 //#####DESCRIPTIONBEGIN####
43 // Author(s): jlarmour
44 // Contributors: jlarmour
50 //####DESCRIPTIONEND####
52 //===========================================================================
56 #include <pkgconf/libm.h> // Configuration header
58 // Include the Math library?
61 // Derived from code with the following copyright
64 /* @(#)e_remainder.c 1.3 95/01/18 */
66 * ====================================================
67 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
69 * Developed at SunSoft, a Sun Microsystems, Inc. business.
70 * Permission to use, copy, modify, and distribute this
71 * software is freely granted, provided that this notice
73 * ====================================================
76 /* __ieee754_remainder(x,p)
78 * returns x REM p = x - [x/p]*p as if in infinite
79 * precise arithmetic, where [x/p] is the (infinite bit)
80 * integer nearest x/p (in half way case choose the even one).
82 * Based on fmod() return x-[x/p]chopped*p exactlp.
85 #include "mathincl/fdlibm.h"
87 static const double zero = 0.0;
90 double __ieee754_remainder(double x, double p)
96 hx = CYG_LIBM_HI(x); /* high word of x */
97 lx = CYG_LIBM_LO(x); /* low word of x */
98 hp = CYG_LIBM_HI(p); /* high word of p */
99 lp = CYG_LIBM_LO(p); /* low word of p */
104 /* purge off exception values */
105 if((hp|lp)==0) return (x*p)/(x*p); /* p = 0 */
106 if((hx>=0x7ff00000)|| /* x not finite */
107 ((hp>=0x7ff00000)&& /* p is NaN */
108 (((hp-0x7ff00000)|lp)!=0)))
112 if (hp<=0x7fdfffff) x = __ieee754_fmod(x,p+p); /* now x < 2p */
113 if (((hx-hp)|(lx-lp))==0) return zero*x;
125 if(x>=p_half) x -= p;
128 CYG_LIBM_HI(x) ^= sx;
132 #endif // ifdef CYGPKG_LIBM