Single Cycle MIPS - addi & jal instruction

Thread Starter


Joined Oct 19, 2010
Will someone please assist me with the following problem? I am extremely confused and frustrated at this point, and appreciate any help available.

I am given the following figure (attached) for a single-cycle MIPS. This figure is shown implementing the jump instruction.

The truth table for the above figure is also attached.

The problem asks me to add the instruction, addi (add immediate) & jal (jump and link), to the figure.

I know that to add the addi instruction, there will be no change in the datapath. However, I am having a difficult time trying to understand how the truth table works based on the addi instruction. The only truth table I understand for the control unit is the one below:

How does R-Format, lw, sw, and beq apply to an instruction such as addi and jal? And how would I go about finding the values for these in the truth table?

My many thanks in advance!