Microprocessor

Data Transfer Instructions In 8085

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There are 5 types of instructions sets are available in the 8085 microprocessor. Today we are going to learn about the data transfer instructions in 8085 microprocessor.

Data transfer instructions in 8085 microprocessors are used to move data between processor registers, memory, and I/O devices.

Data transfer instructions copied data from source to destination without modifying the contents of the source.

The various types of data transfer that are possible between direct data, registers, and memory locations are as follows:

Sr. No	Data Transfer	Example
1.	Between registers	Register B -> Register D
2.	Specific data byte to register or a memory location	Data Byte -> Register B
3.	Between memory location and register	Memory Location -> Register A
4.	Between the I/O device and the accumulator	Input Device -> Register A
5.	Between a register pair and the stack	Register Pair data -> Stack Location

The data transfer instructions in 8085 include the following instructions:

1.	MOV R_d, R_s	2.	MOV R, M	3.	MOV M, R
4.	MVI R, data	5.	MVI M, data	6.	LXI R_p, 16-bit data
7.	LDA address	8.	STA address	9.	LHLD address
10.	SHLD address	11.	LDAX R_p	12.	STAX R_p
13.	XCHG

Now, we will see each instruction which we have to describe above table in detail.

Table of Contents

MOV R_d, R_s

Mnemonics	MOV R_d, R_s
Operation	R_d = R_s
No. of Bytes	1 byte
Machine Cycles	1 (OF)

Algorithm	R_d <- R_s
Flags	No flags are modified
Addr. Mode	Register addressing mode
T-States	4

Description	This instruction copies data from source register R_d to the destination register R_s. The source register Rd and destination register Rs can be any general-purpose register like A, B, C, D, E, H, or L. The contents of the source register remain unchanged.
Example MOV C, M	This instruction will copy the contents of register C to register B. The contents of register C remain unchanged. Example MOV B, C Suppose B = 20H, C = 10H and the instruction MOV B, C is executed. After the execution B 10H and C= 10H.

Machine Cycle Details:

Opcode Fetch : For this cycle the addressgiven by program counter. The program counter places the address on the lower order address bus and the higher order address bus. The program counter is incremented by one to point to next instruction.