static inline unsigned long xchg_u32()

in include/asm/cmpxchg.h [126:170]

• 43 lines of code
• 1 McCabe index (conditional complexity)

static inline unsigned long xchg_u32(volatile int * m, unsigned long val)
{
#if XCHAL_HAVE_EXCLUSIVE
	unsigned long tmp, result;

	__asm__ __volatile__(
			"1:     l32ex   %[result], %[addr]\n"
			"       mov     %[tmp], %[val]\n"
			"       s32ex   %[tmp], %[addr]\n"
			"       getex   %[tmp]\n"
			"       beqz    %[tmp], 1b\n"
			: [result] "=&a" (result), [tmp] "=&a" (tmp)
			: [val] "a" (val), [addr] "a" (m)
			: "memory"
			);

	return result;
#elif XCHAL_HAVE_S32C1I
	unsigned long tmp, result;
	__asm__ __volatile__(
			"1:     l32i    %[tmp], %[mem]\n"
			"       mov     %[result], %[val]\n"
			"       wsr     %[tmp], scompare1\n"
			"       s32c1i  %[result], %[mem]\n"
			"       bne     %[result], %[tmp], 1b\n"
			: [result] "=&a" (result), [tmp] "=&a" (tmp),
			  [mem] "+m" (*m)
			: [val] "a" (val)
			: "memory"
			);
	return result;
#else
	unsigned long tmp;
	__asm__ __volatile__(
			"       rsil    a14, "__stringify(TOPLEVEL)"\n"
			"       l32i    %[tmp], %[mem]\n"
			"       s32i    %[val], %[mem]\n"
			"       wsr     a14, ps\n"
			"       rsync\n"
			: [tmp] "=&a" (tmp), [mem] "+m" (*m)
			: [val] "a" (val)
			: "a14", "memory");
	return tmp;
#endif
}