Assembly Programming — Practice MCQs for CCAT

Correct Answer: B — Copies source to destination

MOV copies data from source to destination (source unchanged).

Correct Answer: B — Adds source to destination

ADD: destination = destination + source.

Correct Answer: B — Subtracts source from destination

SUB: destination = destination - source.

Correct Answer: A — Compares by subtracting, sets flags

CMP subtracts without storing result, only sets flags.

Correct Answer: B — Unconditional jump

JMP: unconditional jump to specified address.

Correct Answer: A — Zero flag is set

JZ (Jump if Zero): jumps when ZF=1.

Correct Answer: B — Pushes return address, jumps to subroutine

CALL saves return address on stack and jumps to subroutine.

Correct Answer: B — Returns from subroutine

RET pops return address from stack and returns.

Correct Answer: B — Decrements CX, loops if CX≠0

LOOP decrements CX; if CX≠0, jumps to label.

Correct Answer: A — Loads effective address

LEA (Load Effective Address) loads address, not data.

Correct Answer: B — Copies data from source to destination

MOV copies data from source operand to destination operand. Source remains unchanged.

Correct Answer: B — MOV copies data, XCHG exchanges data between operands

MOV copies from source to destination. XCHG exchanges contents between two operands.

Correct Answer: B — Writes data to stack and decrements SP

PUSH decrements the stack pointer and then copies the operand to the top of stack.

Correct Answer: B — Reads data from stack and increments SP

POP copies data from top of stack to operand and then increments the stack pointer.

Correct Answer: B — Pushes return address and jumps to subroutine

CALL pushes the return address (next instruction) onto stack and then jumps to the subroutine.

Correct Answer: B — Pops return address from stack and jumps to it

RET pops the return address from the stack into IP/PC, returning control to the caller.

Correct Answer: B — CALL saves return address, JMP does not

JMP simply transfers control without saving return address. CALL saves return address on stack for later RET.

Correct Answer: B — Instruction for the assembler, not converted to machine code

Assembler directives (like ORG, EQU, DB) instruct the assembler but are not converted to machine instructions.

Correct Answer: B — Sets the starting address for code/data

ORG (Origin) directive sets the memory address where the following code or data will be placed.

Correct Answer: B — Subtracts operands and sets flags without storing result

CMP subtracts second operand from first, setting flags accordingly, but does not store the result.

Correct Answer: B — Jump if Zero flag is set

JZ (Jump if Zero) transfers control if the Zero flag is set (previous operation result was zero).

Correct Answer: B — They are the same instruction

JE (Jump if Equal) and JZ (Jump if Zero) are identical - both check if Zero flag is set.

Correct Answer: B — Decrements CX and jumps if CX is not zero

LOOP decrements CX (counter) and jumps to target label if CX is not zero, used for counted loops.

Correct Answer: A — Loads effective address into register

LEA (Load Effective Address) calculates and loads the memory address of operand into register, not the value.

Correct Answer: A — No operation - does nothing but consume time

NOP (No Operation) performs no operation. Used for timing delays or reserving space for later patching.