8 Bit Data Transfer Instructions | 8085 Microprocessor

Rd = Destination register

Rs = Source register

Table of Contents

1. MOV   Rd , Rs

Rd & Rs ⇒ A, B, C, D, E, H, L, and M

Instruction word size  ⇒   1 Byte

Operation ⇒ When this instruction will execute the content of source register (Rs) will pass in the destination register (Rd).

[Rd ] ← [Rs ]

Addressing Mode ⇒ Register Addressing Mode

For example:

[A] = 26 H

[C] = F6 H

MOV   A,C

[A] = F6 H

[C] = F6 H

  • M ⇒ It is an 8-bit user-defined register in main memory and its address is the content of HL register pair.

For example:

[H] = 16 H

[L] = 9D H

M = [ [ HL ] ] = [ [ 169D ] ] = 2C H

The above means that data at the address given by HL pair (169D H) is 2C H.

MOV   B,M

[B] = 2C H

2. MVI   R, 8 bit data

R ⇒ A, B, C, D, E, H, L, and M

Instruction word size  ⇒   2 Byte

Operation ⇒ When this instruction will execute the 8-bit data given in the instruction will store in Register R.

[R] ← 8-bit data

Addressing Mode ⇒ Immediate Addressing Mode

For example:

MVI   D,69 H

[D] = 69 H

3. IN   8-bit port address

Instruction word size  ⇒   2 Byte

Operation ⇒ When this instruction will execute the 8-bit data available at the port address given in the instruction will store/pass in Accumulator.

[A] ← 8-bit data at 8-bit port address

Addressing Mode ⇒ Direct Addressing Mode

For example:

8-bit port address = A0 H

Data at A0 H address = F2 H

or

[ [ A0 ] ] = 21 H

IN  A0 H

[A] = 21 H

4. OUT   8-bit port address

Instruction word size  ⇒   2 Byte

Operation ⇒ When this instruction will execute the content of accumulator will available at the 8-bit port address given in the instruction.

[A] → [8-bit port address]

Addressing Mode ⇒ Direct Addressing Mode

For example:

8-bit port address = 53 H

[A] = F2 H

OUT  53 H

Data at 53 H address = F2 H

or

[ [ 53 ] ] = F2 H

 

Note: All above instructions are data transfer instructions, so the status of the flag will not affect.

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