When programming my first games for the Led Matrix of this computer in Assembly, I quickly realized how useful it would be the Shift instructions, for example to move left and right a character.

In case of Left Shift, no problem at all, the 74181 ALU has the instruction A PLUS A (check here), which is the same as multiply by 2, or Left Shift one bit.

Unfortunally the Right Shift instruction is missing in this IC, so I had to implement it with a 74HCT244 (eight tri-state buffer), redirecting bits, such as bit 7 to bit 6, bit 6 to bit 5, and so on... It's a little "ugly" design, as it's the only one instruction computed outside of 74181, but I haven't choice (any idea?)...

We are very close to delivery the "production" version of the Logisim circuit, the 1.0.0 version. The "done" criteria was, since the very beginning, the ability to run simple games. I'm working on a Tetris game and already have a very crude version of an Arkanoid (or Pong).

Thanks for reading.