/*
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/*
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* linux/include/asm-arm/semaphore.h
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* linux/include/asm-arm/semaphore.h
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*/
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*/
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#ifndef __ASM_PROC_SEMAPHORE_H
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#ifndef __ASM_PROC_SEMAPHORE_H
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#define __ASM_PROC_SEMAPHORE_H
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#define __ASM_PROC_SEMAPHORE_H
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/*
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/*
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* This is ugly, but we want the default case to fall through.
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* This is ugly, but we want the default case to fall through.
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* "__down" is the actual routine that waits...
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* "__down" is the actual routine that waits...
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*/
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*/
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extern inline void down(struct semaphore * sem)
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extern inline void down(struct semaphore * sem)
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{
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{
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__asm__ __volatile__ ("
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__asm__ __volatile__ ("
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@ atomic down operation
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@ atomic down operation
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mrs r0, cpsr
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mrs r0, cpsr
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orr r1, r0, #128 @ disable IRQs
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orr r1, r0, #128 @ disable IRQs
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bic r0, r0, #0x80000000 @ clear N
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bic r0, r0, #0x80000000 @ clear N
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msr cpsr, r1
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msr cpsr, r1
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ldr r1, [%0]
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ldr r1, [%0]
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subs r1, r1, #1
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subs r1, r1, #1
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str r1, [%0]
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str r1, [%0]
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orrmi r0, r0, #0x80000000 @ set N
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orrmi r0, r0, #0x80000000 @ set N
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msr cpsr, r0
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msr cpsr, r0
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movmi r0, %0
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movmi r0, %0
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blmi " SYMBOL_NAME_STR(__down)
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blmi " SYMBOL_NAME_STR(__down)
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: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
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: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
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}
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}
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/*
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/*
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* This is ugly, but we want the default case to fall through.
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* This is ugly, but we want the default case to fall through.
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* "__down_interruptible" is the actual routine that waits...
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* "__down_interruptible" is the actual routine that waits...
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*/
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*/
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extern inline int down_interruptible (struct semaphore * sem)
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extern inline int down_interruptible (struct semaphore * sem)
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{
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{
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int result;
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int result;
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__asm__ __volatile__ ("
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__asm__ __volatile__ ("
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@ atomic down operation
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@ atomic down operation
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mrs r0, cpsr
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mrs r0, cpsr
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orr r1, r0, #128 @ disable IRQs
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orr r1, r0, #128 @ disable IRQs
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bic r0, r0, #0x80000000 @ clear N
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bic r0, r0, #0x80000000 @ clear N
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msr cpsr, r1
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msr cpsr, r1
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ldr r1, [%1]
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ldr r1, [%1]
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subs r1, r1, #1
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subs r1, r1, #1
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str r1, [%1]
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str r1, [%1]
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orrmi r0, r0, #0x80000000 @ set N
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orrmi r0, r0, #0x80000000 @ set N
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msr cpsr, r0
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msr cpsr, r0
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movmi r0, %1
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movmi r0, %1
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movpl r0, #0
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movpl r0, #0
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blmi " SYMBOL_NAME_STR(__down_interruptible) "
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blmi " SYMBOL_NAME_STR(__down_interruptible) "
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mov %0, r0"
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mov %0, r0"
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: "=r" (result)
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: "=r" (result)
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: "r" (sem)
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: "r" (sem)
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: "r0", "r1", "r2", "r3", "ip", "lr", "cc");
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: "r0", "r1", "r2", "r3", "ip", "lr", "cc");
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return result;
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return result;
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}
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}
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/*
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/*
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* Note! This is subtle. We jump to wake people up only if
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* Note! This is subtle. We jump to wake people up only if
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* the semaphore was negative (== somebody was waiting on it).
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* the semaphore was negative (== somebody was waiting on it).
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* The default case (no contention) will result in NO
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* The default case (no contention) will result in NO
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* jumps for both down() and up().
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* jumps for both down() and up().
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*/
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*/
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extern inline void up(struct semaphore * sem)
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extern inline void up(struct semaphore * sem)
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{
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{
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__asm__ __volatile__ ("
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__asm__ __volatile__ ("
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@ atomic up operation
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@ atomic up operation
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mrs r0, cpsr
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mrs r0, cpsr
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orr r1, r0, #128 @ disable IRQs
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orr r1, r0, #128 @ disable IRQs
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bic r0, r0, #0x80000000 @ clear N
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bic r0, r0, #0x80000000 @ clear N
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msr cpsr, r1
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msr cpsr, r1
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ldr r1, [%0]
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ldr r1, [%0]
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adds r1, r1, #1
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adds r1, r1, #1
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str r1, [%0]
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str r1, [%0]
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orrls r0, r0, #0x80000000 @ set N
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orrls r0, r0, #0x80000000 @ set N
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msr cpsr, r0
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msr cpsr, r0
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movmi r0, %0
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movmi r0, %0
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blmi " SYMBOL_NAME_STR(__up)
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blmi " SYMBOL_NAME_STR(__up)
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: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
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: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
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}
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}
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#endif
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#endif
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