In the implied addressing mode in the 8085 microprocessors, the operand is provided implicitly within the instruction. As the operand is provided implicitly the operand fetch is not required in this addressing mode. In this article, we will explore the implied addressing mode in 8085 microprocessors and discuss operations and examples of implied addressing mode. We will also discuss the advantages, disadvantages and applications of implied mode in 8085.
Table of Content
Implied Addressing Mode in 8085 Microprocessor
The addressing mode in which the operand is given implicitly within the instruction opcode is called implicit addressing mode. In other words, the implicit addressing mode is the mode in which the operand is specified within the instruction opcode. The implied addressing mode is also called the implicit addressing mode because the operand is provided implicitly.
Representation of Instruction in 8085 with Implied Addressing Mode
The below format specifies the instruction of the 8085 microprocessor with implied addressing mode.
|
Opcode |
|---|
Operation of Implied Addressing Mode
In the implied addressing mode, we get the operand inside the instruction only and we do not have to fetch the operand from any other location or calculate any effective address. So, in implied addressing mode we do not require any external operation to be performed.
Examples of Implied Addressing Mode in 8085 Microprocessor
Some of the examples of implied addressing mode in 8085 microprocessor is given below.
|
Instruction of 8085 microprocessor (Implied addressing mode used) |
Description |
|---|---|
|
CMA |
1’s Complement the content present in the accumulator. |
|
RRC |
Rotate content of accumulator 1-bit right |
|
RLC |
Rotate content of accumulator 1-bit left |
XCHG Instruction in Detail
The XCHG is an instruction used to exchange the values of HL register pair with DE register pair. The content in the H register is exchanged with D register and the content in the L register is exchanged with E register. Consider the data in HL register is 3259H and the data in DE is E3F2H. After executing the XCHG instruction the HL register contains E3F2H and DE register contains 3259H.
Content Training Table
The content training table for above instruction is given below.
|
Register |
Before Executing XCHG |
After Executing XCHG |
|---|---|---|
|
HL register |
3259H |
E3F2H |
|
DE register |
E3F2H |
3259H |
|
Address |
Hexadecimal Opcode |
Instruction |
Description |
|---|---|---|---|
|
3002 |
EB |
XCHG |
It swaps the content of HL and DE registers. |
Timing Diagram of XCHG Instruction
The timing diagram below shows the XCHG instruction.
XCHG Instructions
Advantages and Disadvantages of Implied Addressing Mode
Some of the advantages and disadvantages of implied addressing mode are listed below.
Advantages of Implied Addressing Mode
Some of the advantages of implied addressing mode are listed below.
- Makes the instruction length shorter.
- It executes faster as no operand fetch is required.
- Implied addressing mode is simple and efficient.
Disadvantages of Implied Addressing Mode
Some of the disadvantages of implied addressing mode are listed below.
- It is not flexible addressing mode.
- It is limited to some operands only.
- It is complex when number of registers are more.
Applications of Implied Addressing Mode in 8085 Microprocessors
Some of the applications of implied addressing mode are listed below.
- Implied addressing mode is used to design zero address instruction.
- Implied mode is used to perform various operations in the .
- It is also used in control instructions as no operand is required in these types of instruction.
Conclusion
From the above discussion we can conclude that in the implied addressing mode the operand is specifies=d within the instruction opcode and no operand fetch is required in the instructions using the implied addressing mode. It also shortens the length of the instruction.
Implied Addressing Mode in 8085 Microprocessor – FAQs
What are Addressing Modes?
The addressing mode gives the information about where the operand is stored and how to calculate the effective address of the operand. In branch instructions it gives target address.
What are Different Types of Addressing Modes in 8085 Microprocessor?
The different types of addressing modes in 8085 microprocessors are:
- Immediate Addressing Mode
- Direct Addressing Mode
- Register Indirect Addressing Mode
- Implied/ Implicit Addressing Mode
- Relative Addressing Mode
What is Effective Address?
The address where the operand is present is called as effective address.