# 3-bit circular shift circuit basic question

Discussion in 'Electronic Design' started by Eric K., Sep 13, 2004.

1. ### Eric K.Guest

I am taking a computer architecture course and got a question that
maybe someone can help with regarding a "3-bit circular shift
circuit". Given a 3-bit input A2A1A0 the circuit returns output
A1A0A2, how to devise a truth table with input A2, A1, A0 and output
A1, A0, A2? What are the three Boolean functions from the truth table:
one function for each of the three outputs?

Thanks!

2. ### Keith WilliamsGuest

At least you're being honest.
You know what the stat is now, and the next state is. That's all you
need. For each current state of A2A1A0, write the next state of these
three variables. You now have your truth table. (hint: you should
have eight entries in your truth table, ...or one .
What is the next value of A2, given the current value of A2A1A0?
What is the next value of A1, given the current value of A2A1A0?
What is the next value of A0, given the current value of A2A1A0?

You now have your three boolean functions.  