Question

Which instruction of the following makes the execution back to the invoking program?

• A. forward
• B. return
• C. data
• D. line

Hint:

CALL → go to subroutine, RET → come back.

Answer 1

The Correct Option is B

Step 1: Recall how a subroutine call works.
When a program executes a CALL instruction, the processor does two things, it saves the address of the instruction right after the call onto the stack, and then it jumps to the start of the subroutine.
Step 2: See what needs to happen when the subroutine finishes.
Once the subroutine has done its job, execution has to come back to exactly where it left off in the calling program, otherwise the rest of the original program would never run.
Step 3: Identify the instruction that does this.
The return instruction is what performs this handoff, it pops the saved address back off the stack and loads it into the program counter, sending control right back to the instruction following the original call.
\[ \boxed{\text{return}} \]