Modes of Addressing (OCR A-Level Computer Science): Flashcards
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What do addressing modes define?
What do addressing modes define?
How instructions identify data location in memory
What are the 4 main addressing modes?
What are the 4 main addressing modes?
Immediate, direct, indirect, indexed
Where is the operand in immediate addressing?
Where is the operand in immediate addressing?
Specified directly in the instruction itself
Immediate addressing main advantage
Immediate addressing main advantage
Fast - no memory lookup required
Immediate addressing use case
Immediate addressing use case
Loading constant values quickly
Immediate addressing disadvantage
Immediate addressing disadvantage
Not flexible - value is fixed in instruction
What does direct addressing specify?
What does direct addressing specify?
Memory address where data is located
Direct addressing use case
Direct addressing use case
Accessing specific fixed memory locations directly
Indirect addressing pointer concept
Indirect addressing pointer concept
Address where actual data address is stored
Indirect addressing disadvantage
Indirect addressing disadvantage
Slower - requires extra memory lookup
Indirect addressing ideal for
Indirect addressing ideal for
Dynamic data structures like linked lists
Indexed addressing calculation
Indexed addressing calculation
Base address + index register offset
Indexed addressing common use
Indexed addressing common use
Iterating over arrays or lists
Indexed addressing limited by
Indexed addressing limited by
Size of the index register