Let us assume that 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?

See explaination for the details.

Explanation:

PC can be any valid value that is divisible by 4. In that case, lets pick 20000.

We can pick any instruction dat writes to a register. Lets pick addi.

The destination register number must be odd so that it has good value of 1. The opposite of the stock-add-value we want to test for. Lets go ahead and pick register 9.

Make register 9 have a value of 20 and register 9 jas a value of 25 prior to the add instruction.

addi. $9, zero, 22

When the value read from register 8 after the add instruction is 22, we know that we have found the fault.

hey! im not 100 percent sure but im pretty sure that what you want to do is not possible : (

explanation: