Atomic compare_and_swap function

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originally posted by hippo@Nov 7 2006, 12:47 AM

look in include/asm (ie, asm-nios2nommu) /system.h

use,

local_irq_save(x) // to disable global irq

then,

local_irq_restore(x) // to enable/restore global irq

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Thank you, hippo!

F.Y.I.

Use the macro COMPARE_AND_SWAP in stead of the function compare_and_swap.

E.g.

static inline int __compare_and_swap(volatile int *p, int old_val, int new_val)

{

int result;

unsigned long int_context;

/* save int. and disable all interrupts */

local_irq_save(int_context);

result = compare_and_swap((volatile long*)p, old_val, new_val);

/* re-enable interrupt */

local_irq_restore(int_context);

return result;

}

# define COMPARE_AND_SWAP(addr, old_val, new_val)

__compare_and_swap(addr, old_val, new_val) http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif