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/*
* linux/include/asm-arm/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)
{
unsigned int cpsr, temp;
__asm__ __volatile__ ("
@ atomic down operation
mrs %0, cpsr
orr %1, %0, #128 @ disable IRQs
bic %0, %0, #0x80000000 @ clear N
msr cpsr, %1
ldr %1, [%2]
subs %1, %1, #1
orrmi %0, %0, #0x80000000 @ set N
str %1, [%2]
msr cpsr, %0
movmi r0, %2
blmi " SYMBOL_NAME_STR(__down_failed)
: "=&r" (cpsr), "=&r" (temp)
: "r" (sem)
: "r0", "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)
{
unsigned int cpsr, temp;
__asm__ __volatile__ ("
@ atomic down interruptible operation
mrs %0, cpsr
orr %1, %0, #128 @ disable IRQs
bic %0, %0, #0x80000000 @ clear N
msr cpsr, %1
ldr %1, [%2]
subs %1, %1, #1
orrmi %0, %0, #0x80000000 @ set N
str %1, [%2]
msr cpsr, %0
movmi r0, %2
movpl r0, #0
blmi " SYMBOL_NAME_STR(__down_interruptible_failed) "
mov %1, r0"
: "=&r" (cpsr), "=&r" (temp)
: "r" (sem)
: "r0", "lr", "cc");
return temp;
}
/*
* 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)
{
unsigned int cpsr, temp;
__asm__ __volatile__ ("
@ atomic up operation
mrs %0, cpsr
orr %1, %0, #128 @ disable IRQs
bic %0, %0, #0x80000000 @ clear N
msr cpsr, %1
ldr %1, [%2]
adds %1, %1, #1
orrls %0, %0, #0x80000000 @ set N
str %1, [%2]
msr cpsr, %0
movmi r0, %2
blmi " SYMBOL_NAME_STR(__up_wakeup)
: "=&r" (cpsr), "=&r" (temp)
: "r" (sem)
: "r0", "lr", "cc");
}
#endif
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