* Status Register (SR): This 16‑bit register comprises an 8‑bit system byte (accessible only in supervisor mode) and an 8‑bit user byte known as the condition code register (CCR). The CCR contains the standard flags—zero (Z), carry (C), overflow (V), negative (N), and extend (X). Notably, the extend bit is used in multi‑precision arithmetic to propagate carries between successive 16‑bit operations, which is critical given that the ALU is only 16 bits wide.
== Instruction Set and Addressing Modes ==
The Motorola 68000 was renowned for its rich, orthogonal instruction set: