-/*
- * Compare and exchange:
- * - returns failure (0) if the location did not contain the old value,
- * - returns success (1) if the location was set to the new value.
- */
-static inline uint32_t
-atomic_cmpxchg(uint32_t *p, uint32_t old, uint32_t new)
-{
- uint32_t res = old;
-
- __asm__ volatile(
- "lock; cmpxchgl %1,%2; \n\t"
- " setz %%al; \n\t"
- " movzbl %%al,%0"
- : "+a" (res) /* %0: old value to compare, returns success */
- : "r" (new), /* %1: new value to set */
- "m" (*(p)) /* %2: memory address */
- : "memory");
- return (res);
-}
-