static inline int arch_spin_trylock()

in include/asm/spinlock.h [35:61]

• 24 lines of code
• 3 McCabe index (conditional complexity)

static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
	u32 tmp, contended, res;
	u32 ticket_next = 1 << TICKET_NEXT;
	u32 *p = &lock->lock;

	do {
		asm volatile (
		"	ldex.w		%0, (%3)   \n"
		"	movi		%2, 1	   \n"
		"	rotli		%1, %0, 16 \n"
		"	cmpne		%1, %0     \n"
		"	bt		1f         \n"
		"	movi		%2, 0	   \n"
		"	add		%0, %0, %4 \n"
		"	stex.w		%0, (%3)   \n"
		"1:				   \n"
		: "=&r" (res), "=&r" (tmp), "=&r" (contended)
		: "r"(p), "r"(ticket_next)
		: "cc");
	} while (!res);

	if (!contended)
		smp_mb();

	return !contended;
}