| David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 1 | /* 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 | |
| 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 Licence 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 Licence for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public Licence |
| 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 { |
| 29 | SItype low; |
| 30 | SItype high; |
| 31 | }; |
| 32 | |
| 33 | union DIunion { |
| 34 | struct DIstruct s; |
| 35 | DItype ll; |
| 36 | }; |
| 37 | |
| 38 | DItype __ashrdi3(DItype u, word_type b) |
| 39 | { |
| 40 | union DIunion w; |
| 41 | union DIunion uu; |
| 42 | word_type bm; |
| 43 | |
| 44 | if (b == 0) |
| 45 | return u; |
| 46 | |
| 47 | uu.ll = u; |
| 48 | |
| 49 | bm = (sizeof(SItype) * BITS_PER_UNIT) - b; |
| 50 | if (bm <= 0) { |
| 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 | } else { |
| 55 | USItype carries = (USItype)uu.s.high << bm; |
| 56 | w.s.high = uu.s.high >> b; |
| 57 | w.s.low = ((USItype)uu.s.low >> b) | carries; |
| 58 | } |
| 59 | |
| 60 | return w.ll; |
| 61 | } |