But otherwise I was understandable?
I agree an all-in-hardware solution would be better - in case you have access to CPLD programming tools (and you know how to do this). Probably doing this in gate logic (and using i.e. shift registers and flip-flops for the software part) would be possible too, though I admit after having to replace damaged xor chip once, schmidt trigger twice and hourly removing of a big drop of tin splashed between pins of the nor chip, we were honestly fed up. On schematics it all looked so simple :)