File: /usr/src/linux/arch/mips/math-emu/dp_fint.c

1     /* 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     ieee754dp ieee754dp_fint(int x)
31     {
32     	COMPXDP;
33     
34     	CLEARCX;
35     
36     	if (x == 0)
37     		return ieee754dp_zero(0);
38     	if (x == 1 || x == -1)
39     		return ieee754dp_one(x < 0);
40     	if (x == 10 || x == -10)
41     		return ieee754dp_ten(x < 0);
42     
43     	xs = (x < 0);
44     	if (xs) {
45     		if (x == (1 << 31))
46     			xm = ((unsigned) 1 << 31);	/* max neg can't be safely negated */
47     		else
48     			xm = -x;
49     	} else {
50     		xm = x;
51     	}
52     
53     #if 1
54     	/* normalize - result can never be inexact or overflow */
55     	xe = DP_MBITS;
56     	while ((xm >> DP_MBITS) == 0) {
57     		xm <<= 1;
58     		xe--;
59     	}
60     	return builddp(xs, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);
61     #else
62     	/* normalize */
63     	xe = DP_MBITS + 3;
64     	while ((xm >> (DP_MBITS + 3)) == 0) {
65     		xm <<= 1;
66     		xe--;
67     	}
68     	DPNORMRET1(xs, xe, xm, "fint", x);
69     #endif
70     }
71     
72     ieee754dp ieee754dp_funs(unsigned int u)
73     {
74     	if ((int) u < 0)
75     		return ieee754dp_add(ieee754dp_1e31(),
76     				     ieee754dp_fint(u & ~(1 << 31)));
77     	return ieee754dp_fint(u);
78     }
79