Function atomic_cmpset_32

freebsd/mips/include/atomic.h:370–390

* Atomically compare the value stored at *p with cmpval and if the * two values are equal, update the value of *p with newval. Returns * zero if the compare failed, nonzero otherwise. */

 * zero if the compare failed, nonzero otherwise.
 */
static __inline int
atomic_cmpset_32(__volatile uint32_t *p, uint32_t cmpval, uint32_t newval)
{
	int ret;

	__asm __volatile (
		"1:\tll	%0, %4\n\t"		/* load old value */
		"bne %0, %2, 2f\n\t"		/* compare */
		"move %0, %3\n\t"		/* value to store */
		"sc %0, %1\n\t"			/* attempt to store */
		"beqz %0, 1b\n\t"		/* if it failed, spin */
		"j 3f\n\t"
		"2:\n\t"
		"li	%0, 0\n\t"
		"3:\n"
		: "=&r" (ret), "=m" (*p)
		: "r" (cmpval), "r" (newval), "m" (*p)
		: "memory");

	return ret;
}

/*
 * Atomically compare the value stored at *p with cmpval and if the