Stuck-at-0 Fault for Single Cycle MIPS Signal

Discussion in 'Homework Help' started by tquiva, Nov 5, 2012.

  1. tquiva

    Thread Starter Member

    Oct 19, 2010
    I have already attempted at this problem, but am still unsure about some parts.

    The problem is:

    Signal: Add unit in upper right corner, ALU result, bit 0

    Let us assume that the processor testing is done by filling the PC, registers, and data and instruction memories with some values (you can choose which values), letting a single instruction execute, then reading the PC, memories, and registers. These values are then examined to determine if a particular fault is present. Can you design a test (values for PC, memories, and registers) that would determine if there is a stuck-at-0 fault on this signal?

    (Single Cycle MIPS attached below)

    My answer:
    To test for a stuck-at-0 fault on a wire, an instruction that puts that wire to a value of 1 is needed. Furthermore, the instruction must have a different result if the value on the wire is at 0.

    I am thinking an addi instruction is needed here? Or would I need to check it first using bne? I'm lost now..

    If anyone could please help me with this, I highly appreciate it.