ARM: Stacks, Subroutines, and Recursion

These flashcards cover key concepts related to ARM stacks, subroutines, and recursion as discussed in the lecture.

Subroutine

A set of instructions designed to perform a frequently used operation.

Stack Pointer

A register that points to the top of the current stack frame.

Link Register

A register used to store the return address of a subroutine and preserves return address from being overwritten by nested calls.

Stack Frame

Memory that stores local variables and register values for a particular function call.

Recursion

A programming technique where a function calls itself in order to solve a problem.

APCS

The ARM Procedure Call Standard which defines how registers are used in subroutines.

STMFD Rd!, {...} (Store Multiple Full Descending)

An instruction to push multiple registers onto the stack.

LDMFD R13!, {...} (Load Multiple From Descending)

An instruction to pop multiple registers from the stack.

Local Variables

Variables that are only accessible within a specific function's stack frame.

Caller

The function that makes a call to another function.

Callee

The function that is called by another function.

Frame Pointer

A register that helps in accessing function parameters and local variables using fixed offsets.

Non-leaf function

A function that calls other functions, requiring preservation of the link register.

Leaf function

A function that does not call any other functions, thus does not need to preserve the link register.

Infinite Loop

A situation in programming where a function calls itself indefinitely due to lack of an exit condition.

Branch Link

Branch and store return address in Link Register