Prerequisite – Addressing Modes
1. Direct Addressing Mode:
In direct addressing mode, the address field contains the address of the operand.
Effective Address (EA) = address field of operand
Example: Add the contents of register 1001 to the accumulator.
Only a single memory reference is required to access data. So no additional calculations are required to work out effective address.
2. Immediate Addressing Mode:
In immediate addressing mode, the operand is a part of the instruction.
Here the Operand = Address Field
Example: Add 5 to the accumulator.
No memory reference is required to fetch data. So no additional calculations are required to work out the effective address. It is a fast method. But the downside is that it has a limited range.
Now let’s compare Direct and Immediate addressing modes.
|Direct Addressing Mode||Immediate Addressing Mode|
|Address fields contains the effective address of operand||There is no address field as the operand is a part of the instruction.|
|It requires one reference to memory.||It does not require any reference to memory.|
|It is slower compared to immediate mode.||It is a faster process.|
|It has more range than in immediate mode.||It has a limited range.|
|Example: Add (1001)||Example: ADD 5|
Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.
- Difference between Indirect and Immediate Addressing Modes
- Difference between Implied addressing mode and Immediate addressing mode
- Difference between Direct and Indirect Addressing Modes
- Difference between Direct and Implied Addressing Modes
- Difference between Relative Addressing Mode and Direct Addressing Mode
- Difference between Indirect and Implied Addressing Modes
- Difference between Memory based and Register based Addressing Modes
- Difference between PC relative and Base register Addressing Modes
- Addressing Modes
- Addressing modes in 8086 microprocessor
- Addressing modes in 8085 microprocessor
- How to execute a 11-digit instruction using different addressing modes in Python?
- 8085 program to swap two 16 bit numbers using Direct addressing mode
- 8085 program to swap two 8 bit numbers using Direct addressing mode
- Difference between Deferred update and Immediate update
- Difference between Simplex, Half duplex and Full Duplex Transmission Modes
- What is the difference between fopen modes “r+”, "rw+" and “w+” in PHP?
- Difference between Direct and Arbitrated Digital Signature
- Removing Direct and Indirect Left Recursion in a Grammar
- Class 8 NCERT Solutions - Chapter 13 Direct and Inverse Proportions - Exercise 13.1
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.