> At this point Player 1 score increments, but there's some slight graphics garbage, a stray line written to the score.
This happens with all games and I think I know the reason. The way I build up the display is some kind of sample-and-hold of the current video signal. You could say the pixel value is latched in the bitmap. On a real monitor, however, a very short pulse would not be visible, because it won't pass the filters that are in the video amplifier etc.
Now it happens that the logic decoding the on-screen 7-segment areas of the score seems to generate very short yet invalid signals. It's most probably related to the fact that the horizontal and vertical counters are ripple counters which have intermediate values while the 4 flipflops in each are changing. So you wouldn't see a 10ns pulse on a monitor, but you will see it in the emulation, if it is latched for the duration of an entire pixel, i.e. 2 clock pulses.
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Re: Space Race (non-) progress
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Space Race (non-) progress
