Tues, 10th Nov 2015, 22:03 Re: Question about control signals -- THIS ONE YOU SHOULD READ

A student writes:

> Dr. Patt,
> I was wondering if we need to know the control signal values i.e. 00 on
> ALUK/2 = ADD; if so is the convention in the book listed on table C.1 start
> with 0 and move forward from there. I apologize if this is an irrelevant
> question  that has already been answered but some clarification is
> appreciated.
> <<name withheld to protect the student who wants to use ADD, not 00>>

The question is not irrelevant and allows me to tell the whole class, and
perhaps stop students from worrying about the codes for each control signals.

So, for example, ALUK can be ADD, AND, NOT, and PASS_A.  If I ask you for the
control signals in a particular instance for ALUK, I am perfectly happy with
one of the four answers above, and not have you worry about which one is
00, 01, 10, and 11.

Good luck on the exam tomorrow.

Yale Patt