The document discusses the instruction set of the 8085 microprocessor. It is divided into 5 categories: 1) Data Transfer Instructions which move data between registers and memory, 2) Arithmetic Instructions which perform addition, subtraction, incrementing and decrementing, 3) Logical Instructions which perform logical operations like AND, OR, XOR, 4) Branching Instructions which alter program flow unconditionally or conditionally, and 5) Control Instructions which control the operation of the microprocessor like halt. Examples of instructions from each category are provided.

1. INSTRUCTION SET OF
8085
Submitted by:-
Rahul Sahu
M.Sc.- Physics 1st
Sem
Guidance by:-
Mr. Goverdhan
Yadu

2. Synopsis:-
• Definition
• Classification
• Explain It’s Type with example

3. What is Instruction set ?
The entire group of instructions that a
microprocessor supports is called Instruction
Set. 8085 has 256 instructions. Each
instruction is represented by an 8-bit binary
value. These 8-bits of binary value is called Op-
Code or Instruction Byte.

4. Classification of Instruction
Set:-
1. Data Transfer Instruction
2. Arithmetic Instructions
3. Logical Instructions
4. Branching Instructions
5. Control Instructions

5. Data Transfer Instructions:-
These instructions move data between
registers, or between memory and registers .
This instructions is used to copy the data
from source to destination or one place to
another . While copying, the contents of
source are not modified.
Example
(1) MOV:- This instruction used to copy data .
• MOV Rd , Rs- This instruction copies the content
of Rs to Rd.
• MOV M , Rs- This instruction copies the content of
register Rs to memory location pointed by H-L
Pair.

6. Data Transfer Instructions:-
(2).MVI:- Move immediate data to a register or
memory location.
• MVI Rd , #30H- 30H is stored in Register Rd.
(3).LDA:- This instruction copies the data from a
given 16 bit address to the accumulator.(Load
Accumulator)
• LDA 3000H- Content of memory location 3000H is
copied in accumulator .
(4).LXI:- This instruction loads 16-bit data in the
register pair designated in the operand.
• LXI H , 2034H- 2034H is stored in H-L pair so
that it act as memory pointer.

7. Data Transfer Instructions:-
(5).STA:- The Content of accumulator are
copied into the memory location .
• STA 3000H- The content of the
accumulator is stored into the memory
location 3000H.

8. Arithmetic Instructions:-
Arithmetic Instructions are the
instructions which perform basic
arithmetic operations such as addition,
subtraction and a few more. In 8085
microprocessor, the destination operand is
generally the accumulator.
These instructions perform the operations
like:
 Addition
 Subtraction
 Increment
 Decrement

9. Arithmetic Instructions:-
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
(6).ADD B- it adds the content of accumulator to
the content of the register B.
(7). ADD M- if content is stored in memory location
the it is added with the content stored in
accumulator.
(8). ADC R or M- Add register or memory to
accumulator with carry.

10. Arithmetic Instructions:-
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.
Example
(9). SUB R or M- Subtract register or memory from
accumulator.
(10). SBB R or M-Subtract register or memory from
accumulator with borrow.
(11). SUI data - Subtract immediate from
accumulator.

11. Arithmetic Instructions:-
Increment and Decrement:-The 8-bit contents of a
register or a memory location can be incremented
or decremented by 1. The 16-bit contents of a
register pair can be incremented or decremented
by 1. Increment or decrement can be performed on
any register or a memory location.
Example
Increment
(12). INR R or M- Increment register or memory by1
(13). INX H- Increment register pair by 1.
Decrement
(14).DCR R or M-Decrement register or memory by1
(15). DCX H- Decrement register pair by 1.

12. Logical Instructions:-
These instructions perform logical
operations on data stored in registers,
memory and status flags .
The logical operations are:
 AND
 OR
 XOR
 Rotate
 Compare
 Complement

13. Logical Instructions:-
Example
(16). ANA R or M- Logical AND register or memory with
accumulator.
(17). ANI 86H(8 bit data)- Logical AND immediate with
accumulator.
(18). ORA R or M- Logical OR register or memory with
accumulator.
(19). ORI 86H(8 bit data)- Logical OR immediate with
accumulator.
(20). XRI 86H(8 bit data)- XOR immediate with
accumulator.
(21). RLC- Rotate accumulator left.
(22). RRC- Rotate accumulator right.
(23). CMP R or M- Compare register or memory with
accumulator.
(24). CMA- Complement accumulator.

14. Branching Instructions:-
The branching instruction alter the
normal sequential flow. These instructions
alter either unconditionally or
conditionally.
Example
(25).JMP 2034 H(16 bit address)- Jump
unconditionally.
(26). JZ 2034 H(16 bit address)- Jump
conditionally.
(27). CALL 2034 H(16 bit address)- Call
unconditionally.
(28). CZ 2034 H(16 bit address)- Call
conditionally.

15. Control Instructions:-
The control instructions control the
operation of microprocessor.
Example
(29). NOP- No operation is performed.
(30). HLT- The CPU finishes executing the
current instruction and halts any further
execution.
(31). DI- Disable interrupt.
(32). EI- Enable interrupt.