Hi Eric I'll have to try it out. I'm not sure how the intel ones respond. There were suppose to be a couple of block move instructions. They put these in to compete with Z80 ones but never released them as part of the instruction set. This was why I thought there was something extra in the NEC chip. I recall, way back when I was working for Intel that we had a list of the hidden operations that chips did. I could swear that there was something in the NEC 8080A that I'd confirmed by running some code on my Poly-88. I guess my mind is just playing tricks. The 8085 stuff is for real, though. I don't have something easy to test it on. The Poly-88 has a great monitor that I can single step with and examine every thing. I think I have a 8085/8088 S100 board around someplace. Maybe for future fiddling I'll see what it does. If I think of it, I can check the intel 8080A tonight. Later Dwight