On Oct 9, 2017, at 11:29 PM, RussellMc wrote: > This was not the case with the Intel 8080. > This was NOT just a matter of octal versus hex representation but that th= e > 8080 fields were not necessarily ordered left to right and in some cases > were split into two parts where the LSN or LS_Oct could be to the left o= r > right of the MSN and not contiguous. Hmm. Such as? I remember the 8080 as being pretty strictly "=94 (in octal.) (yeah, you may have to get a bit creative to interpret CCC for conditional = instructions as , but I don=92t remember anything as bad as I think y= ou described. (I wrote an 8085 simulator, so I got relatively intimately i= nvolved=85)) The Z80, OTOH, went and used up all the unused and nonsensical values, and = did stuff with a prefix byte, so it got quite a bit uglier=85 BillW --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .