1/* IEEE754 floating point arithmetic
2 * double precision: common utilities
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 *
8 *  This program is free software; you can distribute it and/or modify it
9 *  under the terms of the GNU General Public License (Version 2) as
10 *  published by the Free Software Foundation.
11 *
12 *  This program is distributed in the hope it will be useful, but WITHOUT
13 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 *  for more details.
16 *
17 *  You should have received a copy of the GNU General Public License along
18 *  with this program; if not, write to the Free Software Foundation, Inc.,
19 *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
20 */
21
22#include "ieee754sp.h"
23#include "ieee754dp.h"
24
25static inline union ieee754dp ieee754dp_nan_fsp(int xs, u64 xm)
26{
27	return builddp(xs, DP_EMAX + 1 + DP_EBIAS,
28		       xm << (DP_FBITS - SP_FBITS));
29}
30
31union ieee754dp ieee754dp_fsp(union ieee754sp x)
32{
33	COMPXSP;
34
35	EXPLODEXSP;
36
37	ieee754_clearcx();
38
39	FLUSHXSP;
40
41	switch (xc) {
42	case IEEE754_CLASS_SNAN:
43		return ieee754dp_nanxcpt(ieee754dp_nan_fsp(xs, xm));
44
45	case IEEE754_CLASS_QNAN:
46		return ieee754dp_nan_fsp(xs, xm);
47
48	case IEEE754_CLASS_INF:
49		return ieee754dp_inf(xs);
50
51	case IEEE754_CLASS_ZERO:
52		return ieee754dp_zero(xs);
53
54	case IEEE754_CLASS_DNORM:
55		/* normalize */
56		while ((xm >> SP_FBITS) == 0) {
57			xm <<= 1;
58			xe--;
59		}
60		break;
61
62	case IEEE754_CLASS_NORM:
63		break;
64	}
65
66	/*
67	 * Can't possibly overflow,underflow, or need rounding
68	 */
69
70	/* drop the hidden bit */
71	xm &= ~SP_HIDDEN_BIT;
72
73	return builddp(xs, xe + DP_EBIAS,
74		       (u64) xm << (DP_FBITS - SP_FBITS));
75}
76