I was wondering if it is possible to replace the tri-state buffer with a transistor and a diode as shown in the image.

In this case a zero will be the same as high impedance. I don't understand why we should make the current flow in the other direction when we output a zero, we could just leave it at zero volts, and with the help of the diode we can prevent the current from going the other way and messing up the data.

This way it will be - as I understand - not connected to the circuit.

As long as we enable just one register, there shouldn't be any problems. This way we could save a lot of transistors and propagation delay.

[![enter image description here](https://i.stack.imgur.com/3eMWU.jpg)](https://i.stack.imgur.com/3eMWU.jpg)