On Sat, 6 Oct 2001, Manuel Polik wrote:
> Within the first ten seconds reviewing it, I think we might get up to
> six bytes out of the vertical sync sequence:
>
> LDX #0
> LDA #$02
> STA WSYNC
> STA WSYNC
> STA WSYNC
> STA VSYNC
> STA WSYNC
> STA WSYNC
> STA WSYNC
> STX VSYNC
>
> Or what is the first triple of STA WSYNC for?
> I've seen that before more than a dozen times in archive sources, might
> be some common 'cloning error' derived from 'How To Draw A Playfield'
> :-)
Hi Manuel,
In theory, proper NTSC is supposed to have three lines of "equalization pulses"
before and after the 3 lines of Vsync. But the 2600 doesn't do equalization.
Hell, it doesn't even do serration during Vsync itself. But it somehow manages
to get away with it. Regarding games that work ok without the equalization,
modern TVs are a lot more forgiving than the ones designed in the 30's, 40's,
and 50's...when all these specs were written. So yes, you can squeeze another
6 bytes and maybe more out of this code.
-Chris
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