Difference Between Direct and Immediate Addressing Modes

Direct Vs. Immediate Addressing Modes: Explore the Difference Between Direct and Immediate Addressing Modes

An addressing mode is a technique that determines an instruction/s operand. A microprocessor mainly helps in the execution of a set of instructions (that the memory stores) for conducting any specific task.

Immediate and Direct addressing modes are two major modes that specify in which way one can access data and info from given memory (when they execute their instructions). There is a primary difference between direct and immediate addressing modes. In a direct addressing mode, the address of the operand effectively stays in the address field of the instruction. Thus, it does not require intermediate memory access. On the other hand, in an immediate addressing mode, the operand becomes a part of any given instruction, and one doesn’t require a memory reference for fetching data.

What is Direct Addressing Mode?

In the case of a direct addressing mode, the address of the operand effectively stays in the address field of the instruction, and it does not require intermediate memory access. It is very rare these days.

Address Field for an Operand – EA (Effective Address)

In the direct addressing mode, we only require a single reference for accessing data. Thus, working out the effective address would not require any additional calculations.

What is Immediate Addressing Mode?

The operand becomes a part of any given instruction in the case of an immediate addressing mode. Here’s how it works:

Address Field = The Operand

One doesn’t require a memory reference for fetching data. Thus, you don’t have to do additional calculations to work out its effective address. This method is comparatively very fast. The only downside is that its range is very limited comparatively.

Let us now compare both of these modes in detail.