In a 4-bit opcode. What is the maximum number of instructions allowed in your instrction set or your PROM? a. 4
b. 8
c. 16
d. 32

(c) 16

Explanation:

An opcode is the short form for operation code which is also called instruction code. This code forms part of the instructions (instruction set) executed by the computer and it tells the computer the actual operation to be performed. The size of the opcode is the number of bits occupied by it. It is related to the instruction set size as follows;

2ˣ = I   (i)

Where;

x = opcode size or bit

I = maximum or total number of instructions allowed

From the question,

x = 4 bits.

Substitute this value into equation (i) as follows;

2⁴ = I

I = 16.

Therefore, the maximum number of instructions allowed in your instruction set or your PROM - Programmable read-only memory - is 16