UGC-NET | UGC NET CS 2016 July – III | Question 3

Which of the following in 8085 microprocessor performs HL = HL + DE ?
(A) DAD D
(B) DAD H
(C) DAD B
(D) DAD SP

Answer: (A)
Explanation: DAD will perform Double addition (16 bit) between HL pair and any other pair of register. Among HL, BC, DE and SP; B, H and D register will be used first.
So, DAD H will do HL = HL + HL;
DAD B will do HL = HL + BC;
DAD D will do HL = HL + DE;
SP is stack pointer and it is not a pair register, DAD SP will do HL = HL + SP;
So, option (A) is correct.
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