8085

[shri]

'DAD' instruction in 8085 works only with the HL pair. I just want to know that whether this instruction involves Accumulator in backend or not. 

[n_scott_pearson]

Oh man, stress my aging brain cells. I haven't looked at this stuff in 40 years!

DAD, Double Register Add, adds the contents of B&C, D&E, H&L or SP to the contents of H&L and places the result in H&L. Forms are:

DAD	B	ADD	HL,BC	09	HL <- HL + BC
DAD	D	ADD	HL,DE	19	HL <- HL + DE
DAD	H	ADD	HL,HL	29	HL <- HL + HL
DAD	SP	ADD	HL,SP	39	HL <- HL + SP

It can affect the Carry bit (CY), but I don't see it touching the Accumulator at all.

...S