Arithmetic Operations
The 8085 microprocessor performs various arithmetic operations, such as addition, subtraction, increment, and decrement. These arithmetic operations have the following mnemonics.
INTRODUCTION TO 8085 ARITHMETIC INSTRUCTIONS
ADD:  Add  Add the contents of a register. 
ADI:  Add Immediately  Add 8bit data. 
SUB:  Subtract  Subtract the contents of a register. 
SUI:  Subtract Immediately  Subtract 8bit data. 
INR:  Increment  Increase the content of register by1. 
DCR:  Decrement  Decrease the content of register by1. 
The arithmetic operations ADD and Subtract are performed in relation to the contents of the accumulator. However, the Increment or the Decrement operations can be performed in any register. The instructions for these operations are explained below:
INSTRUCTIONS
These arithmetic instructions(except INR and DCR)
 assume implicitly that the accumulator is one of the operands.
 modify all the flags according to the data conditions of the result.
 place the result in the accumulator.
 do not affect the contents of the operand register.
The instructions INR and DCR
 affects the content of the specified register.
 affect all flags expect the CY flag.
The descriptions of the instructions (including INR and DCR) are as follows:
Opcode  Operand  Description 
ADD  R  ADD

ADI  8bit  Add Immediately

SUB  R+  Subtract

SUI  8bit  Subtract Immediately

INR  R*  Increment

DCR  R*  Decrement

So, These are the arithmetic operations/ instructions of the 8085 microprocessor.
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