| David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame^] | 1 | /* MN10300 Non-trivial bit operations |
| 2 | * |
| 3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public Licence |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the Licence, or (at your option) any later version. |
| 10 | */ |
| 11 | #include <linux/module.h> |
| 12 | #include <asm/bitops.h> |
| 13 | #include <asm/system.h> |
| 14 | |
| 15 | /* |
| 16 | * try flipping a bit using BSET and BCLR |
| 17 | */ |
| 18 | void change_bit(int nr, volatile void *addr) |
| 19 | { |
| 20 | if (test_bit(nr, addr)) |
| 21 | goto try_clear_bit; |
| 22 | |
| 23 | try_set_bit: |
| 24 | if (!test_and_set_bit(nr, addr)) |
| 25 | return; |
| 26 | |
| 27 | try_clear_bit: |
| 28 | if (test_and_clear_bit(nr, addr)) |
| 29 | return; |
| 30 | |
| 31 | goto try_set_bit; |
| 32 | } |
| 33 | |
| 34 | /* |
| 35 | * try flipping a bit using BSET and BCLR and returning the old value |
| 36 | */ |
| 37 | int test_and_change_bit(int nr, volatile void *addr) |
| 38 | { |
| 39 | if (test_bit(nr, addr)) |
| 40 | goto try_clear_bit; |
| 41 | |
| 42 | try_set_bit: |
| 43 | if (!test_and_set_bit(nr, addr)) |
| 44 | return 0; |
| 45 | |
| 46 | try_clear_bit: |
| 47 | if (test_and_clear_bit(nr, addr)) |
| 48 | return 1; |
| 49 | |
| 50 | goto try_set_bit; |
| 51 | } |