blob: 18ea5f7ed921f50e63fe03117a78cce6cf8a392e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* ashrdi3.c extracted from gcc-2.7.2/libgcc2.c which is: */
2/* Copyright (C) 1989, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
3
4This file is part of GNU CC.
5
6GNU CC is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 2, or (at your option)
9any later version.
10
11GNU CC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GNU CC; see the file COPYING. If not, write to
18the Free Software Foundation, 59 Temple Place - Suite 330,
19Boston, MA 02111-1307, USA. */
20
21#define BITS_PER_UNIT 8
22
23typedef int SItype __attribute__ ((mode (SI)));
24typedef unsigned int USItype __attribute__ ((mode (SI)));
25typedef int DItype __attribute__ ((mode (DI)));
26typedef int word_type __attribute__ ((mode (__word__)));
27
28struct DIstruct {SItype high, low;};
29
30typedef union
31{
32 struct DIstruct s;
33 DItype ll;
34} DIunion;
35
36DItype
37__ashrdi3 (DItype u, word_type b)
38{
39 DIunion w;
40 word_type bm;
41 DIunion uu;
42
43 if (b == 0)
44 return u;
45
46 uu.ll = u;
47
48 bm = (sizeof (SItype) * BITS_PER_UNIT) - b;
49 if (bm <= 0)
50 {
51 /* w.s.high = 1..1 or 0..0 */
52 w.s.high = uu.s.high >> (sizeof (SItype) * BITS_PER_UNIT - 1);
53 w.s.low = uu.s.high >> -bm;
54 }
55 else
56 {
57 USItype carries = (USItype)uu.s.high << bm;
58 w.s.high = uu.s.high >> b;
59 w.s.low = ((USItype)uu.s.low >> b) | carries;
60 }
61
62 return w.ll;
63}