xref: /openbmc/linux/lib/ashrdi3.c (revision 6d99a79c)
1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 2 of the License, or
5  * (at your option) any later version.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * along with this program; if not, see the file COPYING, or write
14  * to the Free Software Foundation, Inc.
15  */
16 
17 #include <linux/export.h>
18 
19 #include <linux/libgcc.h>
20 
21 long long notrace __ashrdi3(long long u, word_type b)
22 {
23 	DWunion uu, w;
24 	word_type bm;
25 
26 	if (b == 0)
27 		return u;
28 
29 	uu.ll = u;
30 	bm = 32 - b;
31 
32 	if (bm <= 0) {
33 		/* w.s.high = 1..1 or 0..0 */
34 		w.s.high =
35 		    uu.s.high >> 31;
36 		w.s.low = uu.s.high >> -bm;
37 	} else {
38 		const unsigned int carries = (unsigned int) uu.s.high << bm;
39 
40 		w.s.high = uu.s.high >> b;
41 		w.s.low = ((unsigned int) uu.s.low >> b) | carries;
42 	}
43 
44 	return w.ll;
45 }
46 EXPORT_SYMBOL(__ashrdi3);
47