Parameter passing in registers in ARM Architecture - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is parameter passing in registers?

It is a method where function arguments are passed using CPU registers instead of memory, making the process faster.

beginner

How many registers are typically used for parameter passing in ARM architecture?

Usually, the first four parameters are passed using registers R0 to R3.

beginner

Why does ARM use registers for passing parameters instead of the stack?

Using registers is faster because accessing registers is quicker than accessing memory (stack).

intermediate

What happens if there are more than four parameters in an ARM function call?

Parameters beyond the first four are passed on the stack in memory.

intermediate

Which ARM registers are used to return values from functions?

Return values are usually placed in register R0, and if needed, R1 can be used for larger values.

In ARM architecture, which registers are primarily used to pass the first four parameters to a function?

A R0 to R3

B R4 to R7

C R8 to R11

D R12 to R15

The ARM calling convention uses registers R0 to R3 to pass the first four parameters.

What happens to parameters beyond the fourth one in ARM function calls?

A They are ignored

B They are passed on the stack

C They are passed in registers R4 and R5

D They are passed via special memory locations

Parameters beyond the first four are passed on the stack in memory.

Why is passing parameters in registers faster than passing them on the stack?

A Registers are closer to the CPU and faster to access

B Stack memory is faster than registers

C Registers can hold unlimited data

D Stack is only used for return addresses

Registers are part of the CPU and provide faster access than memory locations like the stack.

Which register is commonly used to hold the return value of a function in ARM?

A R1

B R2

C R0

D R3

The return value is usually placed in register R0.

If a function has six parameters, how are they passed in ARM architecture?

A All six in registers R0 to R5

B First two in registers, rest on the stack

C All six on the stack

D First four in registers R0 to R3, last two on the stack

The first four parameters go in registers R0 to R3; the remaining parameters are passed on the stack.

Explain how parameter passing works in ARM architecture using registers and stack.

Think about how the CPU accesses data quickly and what happens when there are more parameters than registers.

Describe why ARM architecture uses registers for parameter passing and how return values are handled.

Consider the speed difference between registers and memory, and where the function result is stored.