8051 assembly control flow Will the following code execute only once or loop repeatedly? STAT: MOV A, #01H JNZ STAT

Introduction / Context:
This question checks understanding of the 8051 conditional jump instruction JNZ (jump if A != 0) and how immediate moves affect the accumulator A.

Given Data / Assumptions:

• MOV A, #01H loads accumulator with 0x01 (decimal 1).
• JNZ LABEL branches when accumulator is nonzero.
• No instructions modify A between the move and the jump.

Concept / Approach:
Because A is explicitly loaded with 1 before each JNZ, the zero condition is never met. Therefore, the branch is always taken, forming an infinite loop at STAT.

Step-by-Step Solution:

Verification / Alternative check:
Single-step in a simulator: the program counter toggles between the two instructions indefinitely.

Why Other Options Are Wrong:

• True: Incorrect—code does not execute only once.
• It depends on the initial PSW flags: JNZ depends on A, not PSW flags.
• Only if interrupts are disabled: Interrupts are unrelated to JNZ behavior here.

Common Pitfalls:
Confusing JNZ with conditional flags; on 8051, JNZ checks accumulator zero directly.

Final Answer:
False — the sequence loops forever.