root/src/system/libroot/posix/musl/arch/m68k/atomic_arch.h
#define a_cas a_cas
static inline int a_cas(volatile int *p, int t, int s)
{
        __asm__ __volatile__ (
                "cas.l %0, %2, (%1)"
                : "+d"(t) : "a"(p), "d"(s) : "memory", "cc");
        return t;
}