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informatics

Memory addressing princples

1.

Memory
addressing
princples
LO:
12.3.4.1 explain memory addressing

2.

Revision
Click to start a quiz!
This quiz covers key concepts of Virtual
Machines, Paging, and Segmentation in
operating systems.

Memory
addressing
modes
There are many ways to locate data and
instructions in primary memory and these
methods are called “memory address modes”.
Memory address modes determine the method
used within the program to access data either
from the Cache or the RAM.

4.

What are
these
addressing
modes?
Direct
Indirect
Immediate
We have four addressing modes:
Indexed

5.

Group work
Create a poster about memory addressing
mode(show how memory addressing modes
works and provide examples):
• Direct
• Indirect
• Immediate
• Indexed

6.

Immediate
addressing
LDM
Immediate addressing means that the
data to be used is hard-coded into the
instruction itself.
LDA #8
Answer is: 8

7.

Direct
addressing
LDD
This is a very simple way of addressing
memory - direct addressing means the
code refers directly to a location in
memory
LDA (3001)
Answer is: 859

8.

Indirect
addressing
LDI
Indirect addressing means that the
address of the data is held in an
intermediate location so that the address
is first 'looked up' and then used to locate
the data itself.
LDA [3001]
Answer is: 653

9.

Final address = base address + index
Indexed
Addressing
LDX
Indexed addressing means that the final
address for the data is determined by
adding an offset to a base address.
LDA 3000[2]
Answer is: 1025