Write down the zero-address, one-address, and three-addressinstructions for the expression X=A+B. State any assumptions.

To write down the zero-address, one-address, and three-address instructions for the expression X=A+B, we need to make some assumptions.

Assumptions:

1. The variables X, A, and B are already declared and have valid values assigned to them.
2. The operations supported are addition (+) and assignment (=).

Zero-address instructions:

1. PUSH A
2. PUSH B
3. ADD
4. POP X

One-address instructions:

1. LOAD A
2. ADD B
3. STORE X

Three-address instructions:

1. ADD X, A, B

In zero-address instructions, we use a stack-based approach. We push the values of A and B onto the stack, perform the addition operation, and then pop the result into X.

In one-address instructions, we load the value of A into a register, add the value of B to it, and then store the result in X.

In three-address instructions, we directly perform the addition operation between A and B, and store the result in X.

These instructions assume that the variables A, B, and X are of the same data type and can be added together.