Re: [stella] Thrust 1.0

Subject: Re: [stella] Thrust 1.0
From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 20 Jul 2000 18:24:11 +0200
>The ROM-Banks now start at the adresses $9000, $b000,
>$d000 and $f000, like all later 16k atari games do.
>(This should help to check the ROM with real hardware)

I wasn't able to try out this version on my 7800 RAM cart, sorry. What
I forgot to tell you is that you need proxy routines for all routines
that need to be called from other banks. The proxy code needs to be at
the same address in all banks.

So if you have for example a routine at $f123 at bank 0, a routine at
$fabc at bank 2 and a routine at $fdef in bank 3, then you would create
some code like this:

Jf123B0:   CMP $FFF6
           JMP $9123
JfabcB2:   CMP $FFF8
           JMP $DABC
JfdefB3:   CMP $FFF9
           CMP $FDEF

and put it at the same address in all four banks. Everytime you'd need
to access any of these three routines, you would jump to the proxy. Of
course the startup vector has to go through such a proxy too.

Currently you seem to have blank space after instructions that trigger
the bankswitching in the bank that you want to call a routine in a different
bank from. This wouldn't work in a flat memory mode like on my 7800 RAM cart.

Would it be much work to change your code to act in the described way?

>The only thing that's missing is full PAL support; you
>can only change the timings for NTSC and PAL with the
>right difficulty switch. I don't know if i can make a
>single version which supports both. I still have rom-
>space left (>4K), but i'm running out of time in ntsc-
>mode, and it would cost some extra time to check for
>tv-mode whenever neccessary(speeds, colors...) :-(.
>(BTW: I can't find a nice yellow in the PAL-palette,
>do you know the value for it?)

There isn't a real nice yellow in the PAL palette. The gold/brown at $3x
is probably the closest that you can get. BTW if you have to choose between
PAL colours and PAL frame rate, you should go with PAL colours. Most PAL
TVs can handle 60Hz NTSC games without a problem. Strange looking colours
might be more of a problem.

>Please tell me what you think about the gameplay
>(steering, gravity, fuel, guns, planets 7+8 (if you
>get that far ;-) etc.) and if the difficulty levels
>are ok.

I have only done a very short test on z26 so far, and I think the initial
behaviour of the spaceship is much easier to handle now. I think everyone
should be able to play it with these settings. I might play Thrust a little
more later and let you know what I think, if I notice anything worth

Thanks, Eckhard Stolberg

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