Page 57

Table of Contents

Page 59

58. Another listing of the Registers

Which now also shows register 15 as the multiplier low word. Notice that I have also replaced the separate I/O registers with a single one which is used for both IN and OUT data. There are therefore now 10 general purpose registers available.

The idea of separating the input and output busses of the register file is a good one. It means that the instruction decode unit can access the output of the registers whenever it wants, without stopping the write-back of results to the register file by the units. Effectively then the bus arbitration circuit is always in the result phase, which should dramatically speed up the CPU.