The 8085 instruction set can be classified into the following five functional headings.
1. DATA TRANSFER INSTRUCTIONS:
It includes the instructions that move (copies) data between registers or between memory locations and registers. In all data transfer operations the content of source register is not altered. Hence the data transfer is copying operation.
Ex: (1) Mov A,B (2) MVI C,45H
2. ARITHMETIC INSTRUCTIONS:
Includes the instructions, which performs the addition, subtraction, increment or decrement operations. The flag conditions are altered after execution of an instruction in this group.
Ex: (1) ADD A,B (2) SUI B,05H
3. LOGICAL INSTRUCTIONS:
The instructions which performs the logical operations like AND, OR, EXCLUSIVE- OR, complement, compare and rotate instructions are grouped under this heading. The flag conditions are altered after execution of an instruction in this group.
Ex: (1) ORA A (2) ANI B, 01H
4. BRANCHING INSTRUCTIONS:
The instructions that are used to transfer the program control from one memory location to another memory location are grouped under this heading.
Ex: (1) CALL (2) JMP 4100
5. MACHINE CONTROL INSTRUCTIONS:
It includes the instructions related to interrupts and the instruction used to stop the program execution