i386/linux/linux-2.3.21/include/asm-arm/proc-armv/semaphore.h

   1 /*
   2  * linux/include/asm-arm/semaphore.h
   3  */
   4 #ifndef __ASM_PROC_SEMAPHORE_H
   5 #define __ASM_PROC_SEMAPHORE_H
   6
   7 /*
   8  * This is ugly, but we want the default case to fall through.
   9  * "__down" is the actual routine that waits...
  10  */
  11 extern inline void down(struct semaphore * sem)
  12 {
  13         unsigned int cpsr, temp;
  14
  15         __asm__ __volatile__ ("
  16         @ atomic down operation
  17         mrs     %0, cpsr
  18         orr     %1, %0, #128            @ disable IRQs
  19         msr     cpsr, %1
  20         ldr     %1, [%2]
  21         bic     %0, %0, #0x80000000     @ clear N
  22         subs    %1, %1, #1
  23         str     %1, [%2]
  24         orrmi   %0, %0, #0x80000000     @ set N
  25         msr     cpsr, %0
  26         movmi   r0, %2
  27         blmi    " SYMBOL_NAME_STR(__down_failed)
  28                 : "=&r" (cpsr), "=&r" (temp)
  29                 : "r" (sem)
  30                 : "r0", "lr", "cc");
  31 }
  32
  33 /*
  34  * This is ugly, but we want the default case to fall through.
  35  * "__down_interruptible" is the actual routine that waits...
  36  */
  37 extern inline int down_interruptible (struct semaphore * sem)
  38 {
  39         unsigned int cpsr, temp;
  40
  41         __asm__ __volatile__ ("
  42         @ atomic down interruptible operation
  43         mrs     %0, cpsr
  44         orr     %1, %0, #128            @ disable IRQs
  45         msr     cpsr, %1
  46         ldr     %1, [%2]
  47         bic     %0, %0, #0x80000000     @ clear N
  48         subs    %1, %1, #1
  49         str     %1, [%2]
  50         orrmi   %0, %0, #0x80000000     @ set N
  51         msr     cpsr, %0
  52         movmi   r0, %2
  53         movpl   r0, #0
  54         blmi    " SYMBOL_NAME_STR(__down_interruptible_failed) "
  55         mov     %1, r0"
  56                 : "=&r" (cpsr), "=&r" (temp)
  57                 : "r" (sem)
  58                 : "r0", "lr", "cc");
  59
  60         return temp;
  61 }
  62
  63 extern inline int down_trylock(struct semaphore *sem)
  64 {
  65         unsigned int cpsr, temp;
  66
  67         __asm__ __volatile__ ("
  68         @ atomic down try lock operation
  69         mrs     %0, cpsr
  70         orr     %1, %0, #128            @ disable IRQs
  71         msr     cpsr, %1
  72         ldr     %1, [%2]
  73         bic     %0, %0, #0x80000000     @ clear N
  74         subs    %1, %1, #1
  75         str     %1, [%2]
  76         orrmi   %0, %0, #0x80000000     @ set N
  77         msr     cpsr, %0
  78         movmi   r0, %2
  79         movpl   r0, #0
  80         blmi    " SYMBOL_NAME_STR(__down_trylock_failed) "
  81         mov     %1, r0"
  82                 : "=&r" (cpsr), "=&r" (temp)
  83                 : "r" (sem)
  84                 : "r0", "lr", "cc");
  85
  86         return temp;
  87 }
  88
  89 /*
  90  * Note! This is subtle. We jump to wake people up only if
  91  * the semaphore was negative (== somebody was waiting on it).
  92  * The default case (no contention) will result in NO
  93  * jumps for both down() and up().
  94  */
  95 extern inline void up(struct semaphore * sem)
  96 {
  97         unsigned int cpsr, temp;
  98
  99         __asm__ __volatile__ ("
 100         @ atomic up operation
 101         mrs     %0, cpsr
 102         orr     %1, %0, #128            @ disable IRQs
 103         msr     cpsr, %1
 104         ldr     %1, [%2]
 105         bic     %0, %0, #0x80000000     @ clear N
 106         adds    %1, %1, #1
 107         str     %1, [%2]
 108         orrle   %0, %0, #0x80000000     @ set N
 109         msr     cpsr, %0
 110         movmi   r0, %2
 111         blmi    " SYMBOL_NAME_STR(__up_wakeup)
 112                 : "=&r" (cpsr), "=&r" (temp)
 113                 : "r" (sem)
 114                 : "r0", "lr", "cc");
 115 }
 116
 117 #endif