0,0 → 1,96 |
/* |
* Copyright (C) 2001-2004 Jakub Jermar |
* All rights reserved. |
* |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* are met: |
* |
* - Redistributions of source code must retain the above copyright |
* notice, this list of conditions and the following disclaimer. |
* - Redistributions in binary form must reproduce the above copyright |
* notice, this list of conditions and the following disclaimer in the |
* documentation and/or other materials provided with the distribution. |
* - The name of the author may not be used to endorse or promote products |
* derived from this software without specific prior written permission. |
* |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
*/ |
|
#ifndef __MIPS_ATOMIC_H__ |
#define __MIPS_ATOMIC_H__ |
|
#define atomic_inc(x) (a_add(x,1)) |
#define atomic_dec(x) (a_sub(x,1)) |
|
/* |
* Atomic addition |
* |
* This case is harder, and we have to use the special LL and SC operations |
* to achieve atomicity. The instructions are similar to LW (load) and SW |
* (store), except that the LL (load-linked) instruction loads the address |
* of the variable to a special register and if another process writes to |
* the same location, the SC (store-conditional) instruction fails. |
*/ |
static inline int a_add( volatile int *val, int i) |
{ |
int tmp, tmp2; |
|
asm volatile ( |
" .set push\n" |
" .set noreorder\n" |
" nop\n" |
"1:\n" |
" ll %0, %1\n" |
" addu %0, %0, %2\n" |
" move %3, %0\n" |
" sc %0, %1\n" |
" beq %0, 0x0, 1b\n" |
" move %0, %3\n" |
" .set pop\n" |
: "=&r" (tmp), "=o" (*val) |
: "r" (i), "r" (tmp2) |
); |
return tmp; |
} |
|
|
/* |
* Atomic subtraction |
* |
* Implemented in the same manner as a_add, except we substract the value. |
*/ |
static inline int a_sub( volatile int *val, int i) |
|
{ |
int tmp, tmp2; |
|
asm volatile ( |
" .set push\n" |
" .set noreorder\n" |
" nop\n" |
"1:\n" |
" ll %0, %1\n" |
" subu %0, %0, %2\n" |
" move %3, %0\n" |
" sc %0, %1\n" |
" beq %0, 0x0, 1b\n" |
" move %0, %3\n" |
" .set pop\n" |
: "=&r" (tmp), "=o" (*val) |
: "r" (i), "r" (tmp2) |
); |
return tmp; |
} |
|
|
#endif |