| 摘要 |
A microcontroller routs bits of a PSW to and from a bus depending on a mode. Whenever in a mode compatible with a prior generation microcontroller, address and routing circuitry using decoders and multiplexers, during a read operation, places bits of the PSW of the current generation on the bus at a location of the prior generation microcontroller. In a write operator circuitry also moves bits from the bus in an arrangement compatible with the prior generation and stores them in the arrangement of the current generation. The circuitry also allows various units such as the ALU to update the PSW register bits directly without making a bus transfer. |
