摘要 |
<p>A central processing unit allows a writing address to correspond to a pair of registers. When an instruction produced from an instruction decoder is a data transfer instruction that is being sent to either one of said pair of registers, the data held in either one of said pair of registers is maintained therein and a data from an internal data bus is transferred into the other register between said pair of registers. In the case of a reading instruction, the data are transferred from the registers onto the internal data bus without changing the content of the other register.</p> |