Re: [stella] 3E + interlace woes

Subject: Re: [stella] 3E + interlace woes
From: "B. Watson" <atari@xxxxxxxxxxxxxx>
Date: Fri, 8 Jul 2005 15:46:29 -0400
On Fri, 8 Jul 2005, Eckhard Stolberg wrote:

> I think Andrew posted a couple more notBD binaries in the AtariAge
> forums but that's about it. No-one besides him is currently using
> this bankswitching format, and I'm not sure if Armin ever wrote
> a test binary for himself when he designed the Kroko Cart.

He did, and he sent it to me along with the source. It works, though I had
to reassemble it with TIA_BASE_ADDRESS set to $40: with 3E bankswitching,
it's perfectly OK to access the TIA at $00-$2C, because unlike 3F, this
doesn't trigger a bankswitch. However, Stella doesn't handle this yet
(writes to $00-$3D are just ignored in 3E mode), so his test binary
didn't work as originally assembled. I'll fix this in Stella tonight.

So Alpha 4 will officially support 3E. It still may not be perfectly
emulated, but until more people write 3E games, it's sorta hard to tell.

> z26 supports interlacing only in those video modes that have every
> other scanline blank to simulate a TV display (modes 3, 4 and 5).
> In these modes we just display the first VCS frame in the odd lines
> and the second frame in the even lines to simulate the higher
> resolution with interlacing.

Ahh, OK, that makes more sense. Maybe z26 should spit out an error
message if -! is given with a video mode that doesn't support it?
The manual actually does say it only works with modes 3-5, once I knew
I was looking for it... of course that'd be my fault, since I (re)wrote
that manual myself :)

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