ARM Addressing Modes and Memory Management

These flashcards cover key vocabulary and concepts related to ARM addressing modes, memory management, and instruction sets as presented in the lecture.

Absolute Addressing

A mode where instructions load or store values from a fixed address in memory.

Indirect Addressing

An addressing mode where a register contains the address of the value to be accessed, similar to pointers in C.

Addressing Modes

Mechanisms that manage how memory addresses are calculated and accessed within instructions.

Word in Memory

A data type consisting of four consecutive bytes, aligned on a 4-byte boundary.

Writeback

A feature that allows the address calculated during loading or storing to update the base register automatically.

Pre-index Writeback

An operation that updates the base register while loading data, using the syntax [R0, #4]!

Effective Address

The actual address in memory that is used for loading or storing data, calculated based on the addressing mode.

Memory Alignment

The requirement that data types, like words, must be aligned on specific byte boundaries (e.g., 4 bytes for words) for correct access.

Bit Shifting

An operation that shifts bits to the left or right, effectively multiplying or dividing the number by powers of two.

Arithmetic Shift vs. Logical Shift

Arithmetic shifts maintain the sign of the number by shifting in copies of the sign bit, while logical shifts always fill with zeros.

Position Independence

A code property that allows it to function properly regardless of where it is loaded in memory, relying on relative addressing.

Load and Store Instructions (LDR and STR)

Instructions used to access memory, LDR loads a value and STR stores a value from or into memory.

Immediate Value

A constant value directly encoded in an instruction, used as an operand for operations.

Array Accessing

Using registers to access elements of an array, facilitated by indirect addressing with register indices.

Assembler

A tool that translates assembly code into machine code, handling details like absolute addressing automatically.