Date   : Mon, 23 Jan 1995 16:27:56 +0000
From   : lamcw <lamcw@...>
Subject: REVS Timing

Mark Cooke wrote:

;Well, I hope that my current design
;methodology for my emulator will deal with this correctly.  It does mean a
;bit of extra work keeping the VIA interrupts in sync though.  I currently
;time the machine by using the opcode counters.  Hopefully slight errors
;in timing won't cause a problem.


I found it impossible to keep exact time AND get good performance.
On your faster PCs and in machine code, the task becomes feasible.
It's really only REVS which is fussy which is why gave up and implemented
a REVS cheat. It's a lot of effort just for the benefit of one game.
Getting the timing absolutely bang-on seems to me a real herculian
task. I can just imagine the agony of watching the REVS interrupts
scroll very, very slowly up the screen...


Chris.