If-else implementation in assembly in ARM Architecture - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to compare two registers and branch if equal.

ARM Architecture

CMP R0, R1
BEQ [1]

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AADD

BR2

CMOV

Dlabel_equal

Attempts:

3 left

💡 Hint

Common Mistakes

Using a register instead of a label after BEQ.

Confusing BEQ with MOV or ADD instructions.

The CMP instruction compares two registers. BEQ branches to the label if they are equal.

2fill in blank

medium

Complete the code to load immediate value 1 into R2 if R0 is greater than R1.

ARM Architecture

CMP R0, R1
BGT [1]
MOV R2, #0
B [2]
[1]:
MOV R2, #1
[2]:

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Aset_one

Bend_if

Cstart

Dloop

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same label for both branches.

Forgetting to branch after setting R2 to 0.

BGT branches to set_one if R0 > R1. Otherwise, R2 is set to 0. Then it jumps to end_if to skip the next instruction.

3fill in blank

hard

Fix the error in the code to correctly implement if-else logic.

ARM Architecture

CMP R3, R4
BLT [1]
MOV R5, #10
B [2]
[1]:
MOV R5, #20
[2]:

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Aless_than

Belse_part

Cstart

Dend_if

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect or missing labels.

Not branching after the first MOV instruction.

BLT branches to less_than if R3 < R4. Otherwise, R5 is set to 10, then jumps to end_if to skip the else part.

4fill in blank

hard

Fill both blanks to complete the if-else structure that sets R7 to 5 if R6 equals R8, else sets R7 to 0.

ARM Architecture

CMP R6, R8
BEQ [1]
MOV R7, #0
B [2]
[1]:
MOV R7, #5
[2]:

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Aequal_case

Bend_if

Cstart

Delse_case

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the labels for if and else blocks.

Forgetting the branch after MOV R7, #0.

BEQ branches to equal_case if R6 equals R8. Otherwise, R7 is set to 0, then jumps to end_if to skip the equal case.

5fill in blank

hard

Fill all three blanks to implement if-else that sets R9 to 100 if R10 is not zero, else sets R9 to 50.

ARM Architecture

CMP R10, #0
BNE [1]
MOV R9, #50
B [2]
[1]:
MOV R9, [3]
[2]:

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Anot_zero

Bend_if

C#100

D#0

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong labels or missing branches.

Forgetting the # before immediate values.

BNE branches to not_zero if R10 is not zero. Otherwise, R9 is set to 50, then jumps to end_if. In the not_zero block, R9 is set to 100.