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 "ieee754dp.h"
23
24union ieee754dp ieee754dp_flong(s64 x)
25{
26	u64 xm;
27	int xe;
28	int xs;
29
30	ieee754_clearcx();
31
32	if (x == 0)
33		return ieee754dp_zero(0);
34	if (x == 1 || x == -1)
35		return ieee754dp_one(x < 0);
36	if (x == 10 || x == -10)
37		return ieee754dp_ten(x < 0);
38
39	xs = (x < 0);
40	if (xs) {
41		if (x == (1ULL << 63))
42			xm = (1ULL << 63);	/* max neg can't be safely negated */
43		else
44			xm = -x;
45	} else {
46		xm = x;
47	}
48
49	/* normalize */
50	xe = DP_FBITS + 3;
51	if (xm >> (DP_FBITS + 1 + 3)) {
52		/* shunt out overflow bits */
53		while (xm >> (DP_FBITS + 1 + 3)) {
54			XDPSRSX1();
55		}
56	} else {
57		/* normalize in grs extended double precision */
58		while ((xm >> (DP_FBITS + 3)) == 0) {
59			xm <<= 1;
60			xe--;
61		}
62	}
63
64	return ieee754dp_format(xs, xe, xm);
65}
66