28-12-2012, 05:14 PM
Instruction Set of 8085
[attachment=45647]
Introduction
An instruction is a binary pattern designed inside a
microprocessor to perform a specific function.
The entire group of instructions that a microprocessor
supports is called Instruction Set.
8085 has 246 instructions.
Each instruction is represented by an 8-bit binary value.
These 8-bits of binary value is called Op-Code or
Instruction Byte.
Classification of Instruction Set
Data Transfer Instruction
Arithmetic Instructions
Logical Instructions
Branching Instructions
Control Instructions
Data Transfer Instructions
These instructions move data between registers, or
between memory and registers.
These instructions copy data from source to
destination.
While copying, the contents of source are not
modified.
Addition
Any 8-bit number, or the contents of register, or the
contents of memory location can be added to the
contents of accumulator.
The result (sum) is stored in the accumulator.
No two other 8-bit registers can be added directly.
Example: The contents of register B cannot be added
directly to the contents of register C.
Subtraction
Any 8-bit number, or the contents of register, or the
contents of memory location can be subtracted from
the contents of accumulator.
The result is stored in the accumulator.
Subtraction is performed in 2’s complement form.
If the result is negative, it is stored in 2’s complement
form.
No two other 8-bit registers can be subtracted directly
[attachment=45647]
Introduction
An instruction is a binary pattern designed inside a
microprocessor to perform a specific function.
The entire group of instructions that a microprocessor
supports is called Instruction Set.
8085 has 246 instructions.
Each instruction is represented by an 8-bit binary value.
These 8-bits of binary value is called Op-Code or
Instruction Byte.
Classification of Instruction Set
Data Transfer Instruction
Arithmetic Instructions
Logical Instructions
Branching Instructions
Control Instructions
Data Transfer Instructions
These instructions move data between registers, or
between memory and registers.
These instructions copy data from source to
destination.
While copying, the contents of source are not
modified.
Addition
Any 8-bit number, or the contents of register, or the
contents of memory location can be added to the
contents of accumulator.
The result (sum) is stored in the accumulator.
No two other 8-bit registers can be added directly.
Example: The contents of register B cannot be added
directly to the contents of register C.
Subtraction
Any 8-bit number, or the contents of register, or the
contents of memory location can be subtracted from
the contents of accumulator.
The result is stored in the accumulator.
Subtraction is performed in 2’s complement form.
If the result is negative, it is stored in 2’s complement
form.
No two other 8-bit registers can be subtracted directly