[Solved] In ARM assembly, what is the main effect of executing the BL instruction? — Ans: It branches to a subroutine and saves the return address in the link register. | ARM Architecture

ARM Architecture - Control Flow Instructions

In ARM assembly, what is the main effect of executing the BL instruction?

AIt branches unconditionally without saving any return address.

BIt branches to a subroutine and saves the return address in the link register.

CIt loads a value into the link register without branching.

DIt performs a conditional branch based on the zero flag.

Step-by-Step Solution

Solution:

Step 1: Understand BL instruction
The BL (Branch with Link) instruction branches to a target address and simultaneously stores the return address (the address of the next instruction) in the link register (LR or R14).
Step 2: Compare options
It branches to a subroutine and saves the return address in the link register. correctly describes this behavior. It branches unconditionally without saving any return address. describes a simple branch (B) without link. It loads a value into the link register without branching. is incorrect as BL always branches. It performs a conditional branch based on the zero flag. is incorrect because BL is unconditional.
Final Answer:
It branches to a subroutine and saves the return address in the link register. -> Option B
Quick Check:
BL saves return address in LR and branches [OK]

Quick Trick: BL branches and saves return address in LR [OK]

Common Mistakes:

Master "Control Flow Instructions" in ARM Architecture

9 interactive learning modes - each teaches the same concept differently

More ARM Architecture Quizzes

In ARM assembly, what is the main effect of executing the BL instruction?