9/26/04

A student writes:

     Hey Professor Patt. I had a quick question. I was working on the
     homework problems and I ran into problem #7.

Hey, student xxxxxxxx. Didn't your mother teach you: Hay is for horses...?

     (4.7)
     Suppose a 32-bit instruction takes the following format:

     OPCODE DR SR1 SR2 UNUSED

     If there are 255 opcodes and 120 registers,

     What is the minimum number of bits required to represent the OPCODE?
     What is the minimum number of bits required to represent the Destination
     Register (DR)?
     What is the maximum number of UNUSED bits in the instruction encoding?

     ---When I looked in the textbook, I noticed that it's switched. 4.8 is
     actually the one on the assignment but it's listed as 4.7. I hope you
     got what I am trying to describe to you.

Yeah, I think I figured it out.

     If you just look in the book, I think you will realize what
     I am trying to say.

I almost did not send this to the class, but given that some students may not start doing their homework until Sunday evening, I figured I may as well make sure that no one suffers inordinate anxiety.

So, then: if the number disagrees with the statement of the problem, do the problem stated. OK?
Yale Patt

     Thanks.
     << name withheld to protect yet another accountant in training >>