On Fri, Feb 06, 2015 at 09:35:35AM +0100, Andreas Davour wrote: > On Thu, 5 Feb 2015, dave porter wrote: > > >Octal makes sense for the PDP11 since the instruction > >format is divided into 3-bit fields (operand modes, > >register specifiers, etc). > > > >Hex makes sense for the VAX since the instruction > >format is divided into 4-bit fields (operand modes, > >register specifiers, etc). > > How about PDP10, PDP8, PDP15 and other fun architectures?
Just by looking at DEC front panels (which I've spent a fair amount of time doing :)) you can see that DEC was consistent in grouping bits in fields of three, which translates nicely to octal. This was reflected in most manuals I've read. Look here: http://www.quadibloc.com/comp/pan07.htm Regards, Pontus. _______________________________________________ Simh mailing list [email protected] http://mailman.trailing-edge.com/mailman/listinfo/simh
