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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [arch/] [mips/] [math-emu/] [dp_modf.c] - Blame information for rev 1765

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/* IEEE754 floating point arithmetic
 * double precision: common utilities
 */
/*
 * MIPS floating point support
 * Copyright (C) 1994-2000 Algorithmics Ltd.  All rights reserved.
 * http://www.algor.co.uk
 *
 * ########################################################################
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope 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 this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * ########################################################################
 */
 
 
#include "ieee754dp.h"
 
/* modf function is always exact for a finite number
*/
ieee754dp ieee754dp_modf(ieee754dp x, ieee754dp * ip)
{
        COMPXDP;
 
        CLEARCX;
 
        EXPLODEXDP;
 
        switch (xc) {
        case IEEE754_CLASS_SNAN:
        case IEEE754_CLASS_QNAN:
        case IEEE754_CLASS_INF:
        case IEEE754_CLASS_ZERO:
                *ip = x;
                return x;
        case IEEE754_CLASS_DNORM:
                /* far to small */
                *ip = ieee754dp_zero(xs);
                return x;
        case IEEE754_CLASS_NORM:
                break;
        }
        if (xe < 0) {
                *ip = ieee754dp_zero(xs);
                return x;
        }
        if (xe >= DP_MBITS) {
                *ip = x;
                return ieee754dp_zero(xs);
        }
        /* generate ipart mantissa by clearing bottom bits
         */
        *ip = builddp(xs, xe + DP_EBIAS,
                      ((xm >> (DP_MBITS - xe)) << (DP_MBITS - xe)) &
                      ~DP_HIDDEN_BIT);
 
        /* generate fpart mantissa by clearing top bits
         * and normalizing (must be able to normalize)
         */
        xm = (xm << (64 - (DP_MBITS - xe))) >> (64 - (DP_MBITS - xe));
        if (xm == 0)
                return ieee754dp_zero(xs);
 
        while ((xm >> DP_MBITS) == 0) {
                xm <<= 1;
                xe--;
        }
        return builddp(xs, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);
}

Line No.	Rev	Author	Line
1	1275	phoenix	`/* IEEE754 floating point arithmetic`
2			`* double precision: common utilities`
3			`*/`
4			`/*`
5			`* MIPS floating point support`
6			`* Copyright (C) 1994-2000 Algorithmics Ltd. All rights reserved.`
7			`* http://www.algor.co.uk`
8			`*`
9			`* ########################################################################`
10			`*`
11			`* This program is free software; you can distribute it and/or modify it`
12			`* under the terms of the GNU General Public License (Version 2) as`
13			`* published by the Free Software Foundation.`
14			`*`
15			`* This program is distributed in the hope it will be useful, but WITHOUT`
16			`* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or`
17			`* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License`
18			`* for more details.`
19			`*`
20			`* You should have received a copy of the GNU General Public License along`
21			`* with this program; if not, write to the Free Software Foundation, Inc.,`
22			`* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.`
23			`*`
24			`* ########################################################################`
25			`*/`
26
27
28			`#include "ieee754dp.h"`
29
30			`/* modf function is always exact for a finite number`
31			`*/`
32			`ieee754dp ieee754dp_modf(ieee754dp x, ieee754dp * ip)`
33			`{`
34			`COMPXDP;`
35
36			`CLEARCX;`
37
38			`EXPLODEXDP;`
39
40			`switch (xc) {`
41			`case IEEE754_CLASS_SNAN:`
42			`case IEEE754_CLASS_QNAN:`
43			`case IEEE754_CLASS_INF:`
44			`case IEEE754_CLASS_ZERO:`
45			`*ip = x;`
46			`return x;`
47			`case IEEE754_CLASS_DNORM:`
48			`/* far to small */`
49			`*ip = ieee754dp_zero(xs);`
50			`return x;`
51			`case IEEE754_CLASS_NORM:`
52			`break;`
53			`}`
54			`if (xe < 0) {`
55			`*ip = ieee754dp_zero(xs);`
56			`return x;`
57			`}`
58			`if (xe >= DP_MBITS) {`
59			`*ip = x;`
60			`return ieee754dp_zero(xs);`
61			`}`
62			`/* generate ipart mantissa by clearing bottom bits`
63			`*/`
64			`*ip = builddp(xs, xe + DP_EBIAS,`
65			`((xm >> (DP_MBITS - xe)) << (DP_MBITS - xe)) &`
66			`~DP_HIDDEN_BIT);`
67
68			`/* generate fpart mantissa by clearing top bits`
69			`* and normalizing (must be able to normalize)`
70			`*/`
71			`xm = (xm << (64 - (DP_MBITS - xe))) >> (64 - (DP_MBITS - xe));`
72			`if (xm == 0)`
73			`return ieee754dp_zero(xs);`
74
75			`while ((xm >> DP_MBITS) == 0) {`
76			`xm <<= 1;`
77			`xe--;`
78			`}`
79			`return builddp(xs, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);`
80			`}`

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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [arch/] [mips/] [math-emu/] [dp_modf.c] - Blame information for rev 1765