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/*
* linux/include/asm-arm/proc-armo/semaphore.h
*/
#ifndef __ASM_PROC_SEMAPHORE_H
#define __ASM_PROC_SEMAPHORE_H
/*
* This is ugly, but we want the default case to fall through.
* "__down" is the actual routine that waits...
*/
extern inline void down(struct semaphore * sem)
{
__asm__ __volatile__ ("
@ atomic down operation
mov r0, pc
orr r1, r0, #0x08000000
and r0, r0, #0x0c000003
teqp r1, #0
ldr r1, [%0]
subs r1, r1, #1
str r1, [%0]
mov r1, pc, lsr #28
teqp r0, r1, lsl #28
movmi r0, %0
blmi " SYMBOL_NAME_STR(__down)
: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
}
/*
* This is ugly, but we want the default case to fall through.
* "__down_interruptible" is the actual routine that waits...
*/
extern inline int down_interruptible (struct semaphore * sem)
{
int result;
__asm__ __volatile__ ("
@ atomic down operation
mov r0, pc
orr r1, r0, #0x08000000
and r0, r0, #0x0c000003
teqp r1, #0
ldr r1, [%1]
subs r1, r1, #1
str r1, [%1]
mov r1, pc, lsr #28
orrmi r0, r0, #0x80000000 @ set N
teqp r0, r1, lsl #28
movmi r0, %1
movpl r0, #0
blmi " SYMBOL_NAME_STR(__down_interruptible) "
mov %0, r0"
: "=r" (result)
: "r" (sem)
: "r0", "r1", "r2", "r3", "ip", "lr", "cc");
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
extern inline void up(struct semaphore * sem)
{
__asm__ __volatile__ ("
@ atomic up operation
mov r0, pc
orr r1, r0, #0x08000000
and r0, r0, #0x0c000003
teqp r1, #0
ldr r1, [%0]
adds r1, r1, #1
str r1, [%0]
mov r1, pc, lsr #28
orrls r0, r0, #0x80000000 @ set N
teqp r0, r1, lsl #28
movmi r0, %0
blmi " SYMBOL_NAME_STR(__up)
: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
}
#endif
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