target = &a[2]
			break
		}
		p.errorf("wrong number of arguments to %s instruction", op)
		return
	case 4:
		if p.arch.Family == sys.S390X || p.arch.Family == sys.PPC64 {
			// 4-operand compare-and-branch.
			prog.From = a[0]
			prog.Reg = p.getRegister(prog, op, &a[1])
			prog.AddRestSource(a[2])
			target = &a[3]
			break
		}
		p.errorf("wrong number of arguments to %s instruction", op)
		return