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1 | /* |
1 | /* |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | #ifndef __MIPS_ATOMIC_H__ |
29 | #ifndef __MIPS_ATOMIC_H__ |
30 | #define __MIPS_ATOMIC_H__ |
30 | #define __MIPS_ATOMIC_H__ |
31 | 31 | ||
32 | #define atomic_inc(x) ((*x)++) |
32 | #define atomic_inc(x) (a_add(x,1)) |
33 | #define atomic_dec(x) ((*x)--) |
33 | #define atomic_dec(x) (a_sub(x,1)) |
- | 34 | ||
- | 35 | /* |
|
- | 36 | * Atomic addition |
|
- | 37 | * |
|
- | 38 | * This case is harder, and we have to use the special LL and SC operations |
|
- | 39 | * to achieve atomicity. The instructions are similar to LW (load) and SW |
|
- | 40 | * (store), except that the LL (load-linked) instruction loads the address |
|
- | 41 | * of the variable to a special register and if another process writes to |
|
- | 42 | * the same location, the SC (store-conditional) instruction fails. |
|
- | 43 | */ |
|
- | 44 | static inline int a_add( volatile int *val, int i) |
|
- | 45 | { |
|
- | 46 | int tmp, tmp2; |
|
- | 47 | ||
- | 48 | asm volatile ( |
|
- | 49 | " .set push\n" |
|
- | 50 | " .set noreorder\n" |
|
- | 51 | " nop\n" |
|
- | 52 | "1:\n" |
|
- | 53 | " ll %0, %1\n" |
|
- | 54 | " addu %0, %0, %2\n" |
|
- | 55 | " move %3, %0\n" |
|
- | 56 | " sc %0, %1\n" |
|
- | 57 | " beq %0, 0x0, 1b\n" |
|
- | 58 | " move %0, %3\n" |
|
- | 59 | " .set pop\n" |
|
- | 60 | : "=&r" (tmp), "=o" (*val) |
|
- | 61 | : "r" (i), "r" (tmp2) |
|
- | 62 | ); |
|
- | 63 | return tmp; |
|
- | 64 | } |
|
- | 65 | ||
- | 66 | ||
- | 67 | /* |
|
- | 68 | * Atomic subtraction |
|
- | 69 | * |
|
- | 70 | * Implemented in the same manner as a_add, except we substract the value. |
|
- | 71 | */ |
|
- | 72 | static inline int a_sub( volatile int *val, int i) |
|
- | 73 | ||
- | 74 | { |
|
- | 75 | int tmp, tmp2; |
|
- | 76 | ||
- | 77 | asm volatile ( |
|
- | 78 | " .set push\n" |
|
- | 79 | " .set noreorder\n" |
|
- | 80 | " nop\n" |
|
- | 81 | "1:\n" |
|
- | 82 | " ll %0, %1\n" |
|
- | 83 | " subu %0, %0, %2\n" |
|
- | 84 | " move %3, %0\n" |
|
- | 85 | " sc %0, %1\n" |
|
- | 86 | " beq %0, 0x0, 1b\n" |
|
- | 87 | " move %0, %3\n" |
|
- | 88 | " .set pop\n" |
|
- | 89 | : "=&r" (tmp), "=o" (*val) |
|
- | 90 | : "r" (i), "r" (tmp2) |
|
- | 91 | ); |
|
- | 92 | return tmp; |
|
- | 93 | } |
|
- | 94 | ||
34 | 95 | ||
35 | #endif |
96 | #endif |
36 | 97 |