Re: [stella] Thomas Jentzsch's PAL -> NTSC Conversions

Subject: Re: [stella] Thomas Jentzsch's PAL -> NTSC Conversions
From: Thomas Jentzsch <tjentzsch@xxxxxx>
Date: Thu, 7 Feb 2002 21:54:55 +0100
At 07.02.2002, 18:41, Eckhard Stolberg wrote:
> I've said it before, and I'll say it again. A game need to do
> three complete uninterrupted lines of VSYNC to work properly
> on all TVs. Some games try to use this time to do some other
> setup work (Solaris and Desert Falcon are known offenders in
> this respect) and this seems to to cause problems on some TVs.

I've had a short look at Gas Hog. It does 5 lines of VSYNC and the only
TIA registers it writes to are AUDx1. 

Here is some code:
    ldx    #$2a
    sta    WSYNC
    stx    VBLANK
    stx    VSYNC
    stx    TIM8T
    lda    INTIM
    bne    Lf0a6
    sta    WSYNC
    sta    VSYNC
That look's ok for me too.

What do you mean exactly with uninterrupted?

I'm doing some stuff (SWCHB, RESxy, HMMxy, NUSIZx, VDELPx) during VSYNC
in Thrust and Jammed too and nobody reported any sync problems yet.

Have fun!
Thomas Jentzsch         | *** Every bit is sacred ! ***
tjentzsch at web dot de |

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