File: /usr/src/linux/arch/m68k/lib/ashldi3.c

1     /* ashrdi3.c extracted from gcc-2.95.2/libgcc2.c which is: */
2     /* Copyright (C) 1989, 92-98, 1999 Free Software Foundation, Inc.
3     
4     This file is part of GNU CC.
5     
6     GNU CC is free software; you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation; either version 2, or (at your option)
9     any later version.
10     
11     GNU CC is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15     
16     You should have received a copy of the GNU General Public License
17     along with GNU CC; see the file COPYING.  If not, write to
18     the Free Software Foundation, 59 Temple Place - Suite 330,
19     Boston, MA 02111-1307, USA.  */
20     
21     #define BITS_PER_UNIT 8
22     
23     typedef 	 int SItype	__attribute__ ((mode (SI)));
24     typedef unsigned int USItype	__attribute__ ((mode (SI)));
25     typedef		 int DItype	__attribute__ ((mode (DI)));
26     typedef int word_type __attribute__ ((mode (__word__)));
27     
28     struct DIstruct {SItype high, low;};
29     
30     typedef union
31     {
32       struct DIstruct s;
33       DItype ll;
34     } DIunion;
35     
36     DItype
37     __ashldi3 (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.low = 0;
52           w.s.high = (USItype)uu.s.low << -bm;
53         }
54       else
55         {
56           USItype carries = (USItype)uu.s.low >> bm;
57           w.s.low = (USItype)uu.s.low << b;
58           w.s.high = ((USItype)uu.s.high << b) | carries;
59         }
60     
61       return w.ll;
62     }
63