ORA

 

Syntax: ORA R

Where R can be any of the general purpose registers (A,B,C,D,E,H and L)

Byte: 1byte

Addressing Mode: Register Addressing

Working: 

1.This is 1 byte instruction.

2. Microprocessor will allocate first byte for opcode during execution.

3. During execution of this instruction, microprocessor will perform Logical ORing operation between content of Accumulator and operand register.

4. S, Z, P are modified. Cy and Ac are reset.

Example: ORA B

where [B] = 22H 

and [A]= 11H

After execution of ORA B

[A] =33 H

[B] = 22H

 

 

A= 11 =  0001 0001

B =  22 =0010 0010

 A=33= 0011  0011

FLAG=0000 0100 = 04H