Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it | Date | Mon, 11 Dec 2006 11:04:00 +0000 |
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Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> Yes you can. Well, you can on ARM at least. Between the load exclusive > you can do anything you like until you hit the store exclusive.
How come atomic_set() on arm6 is implemented as:
static inline void atomic_set(atomic_t *v, int i) { unsigned long tmp;
__asm__ __volatile__("@ atomic_set\n" "1: ldrex %0, [%1]\n" " strex %0, %2, [%1]\n" " teq %0, #0\n" " bne 1b" : "=&r" (tmp) : "r" (&v->counter), "r" (i) : "cc"); }
Why LDREX/STREX and not direct assignment?
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