Register Construction: Completed Instruction Register Full Test

Following on from my last post, and after popping in some relays, the instruction register is complete and looks like this:

Completed Instruction Register (front view) Completed Instruction Register (rear view)

As usual I’ve put a video together that demonstrates this card in operation. In this video I give a quick overview of the card and then demonstrate loading values in to the register and instruction bus. I also demonstrate gating part of the instruction bus on to the data bus for the I2B (Immediate to Bus) functionality.

That’s about all there is to say for this card as it’s relatively simple and shares much of its design with the other register cards of the computer. The next card is also a simple one … the decoder. This will take the value on the instruction bus and decide which instruction class it represents. This card will also be the first where I’ll only partially construct it — just enough so that it can handle the SETAB, MOV8 and ALU instruction classes.

Published May 16, 2015