Function atomic_fcmpset_32

freebsd/mips/include/atomic.h:397–425

* 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_fcmpset_32(__volatile uint32_t *p, uint32_t *cmpval, uint32_t newval)
{
	int ret;

	/*
	 * The following sequence (similar to that in atomic_fcmpset_64) will
	 * attempt to update the value of *p with newval if the comparison
	 * succeeds.  Note that they'll exit regardless of whether the store
	 * actually succeeded, leaving *cmpval untouched.  This is in line with
	 * the documentation of atomic_fcmpset_<type>() in atomic(9) for ll/sc
	 * architectures.
	 */
	__asm __volatile (
		"ll	%0, %1\n\t"		/* load old value */
		"bne	%0, %4, 1f\n\t"		/* compare */
		"move	%0, %3\n\t"		/* value to store */
		"sc	%0, %1\n\t"		/* attempt to store */
		"j	2f\n\t"			/* exit regardless of success */
		"nop\n\t"			/* avoid delay slot accident */
		"1:\n\t"
		"sw	%0, %2\n\t"		/* save old value */
		"li	%0, 0\n\t"
		"2:\n"
		: "=&r" (ret), "+m" (*p), "=m" (*cmpval)
		: "r" (newval), "r" (*cmpval)
		: "memory");
	return ret;
}

#define	ATOMIC_CMPSET_ACQ_REL(WIDTH)					\
static __inline  int							\