Question

Explain the following instructions of 8085 Microprocessor with one
example of each : DAD rp

Answer 1

[ADD REGISTER PAIR TO H AND L REGISTER]
Format:[H][L] ← [H][L]+[rh][rI]
Addressing: Register addressing
Group: Arithmetic group
Bytes: 1 byte
Flag: Cy
Comment: The contents of register pair rp are added to the contents of H-L pair. Result is placed in
register H and L. Only carry flag is affected.
Example: Let [H]=03H, [L]=05,[D]=15H and [E]=12H
Instruction: DAD D
After execution:[L]=05+12=17H

[H]=03+15=18H

[H-L]=1817H
In this case, carry flag is reset.