Hi.
I've just run a test:
F1 Spirit only writes the following sequences of values to these
registers:
VDP write register: 02, data = 06, Pattern Name Table 01800
VDP write register: 03, data = 80, Pattern Color Table 02000
VDP write register: 04, data = 00, Pattern Generator Table 00000
VDP write register: 02, data = 0e, Pattern Name Table 03800
VDP write register: 03, data = 7f, Pattern Color Table 00000
VDP write register: 04, data = 07, Pattern Generator Table 02000
The last three values are still active when actually playing the game.
MSX-BASIC writes the following sequence when performing the SCREEN 2
command:
VDP write register: 02, data = 06, Pattern Name Table 01800
VDP write register: 03, data = ff, Pattern Color Table 02000
VDP write register: 04, data = 03, Pattern Generator Table 00000
This should be correct, since NLMSX uses it and it looks alright.
As you can see there is a difference. I hope it helps.
Frits
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf
> Of d-fader
> Sent: Sunday, January 30, 2000 10:36 PM
> To: MSX Mailing List
> Subject: Question about VRAM (for ML coders)
>
>
> Hello people...
>
> So here's the story... TeddyWareZ is gonna make a sequel to f1-spirit
> (hopefully). But we haven't even started testing some things
> and gathered
> information and we already have a question... Here we go...
>
> We first started looking at the original f1-spirit as you
> might can imagine.
> But then I got an idea. I can use the pattern-, name-,
> colour- and sprite
> tables of f1-spirit to make some tests for myself so I can see what's
> possible without having to draw my own patterns and stuph (WE
> WON'T STEAL
> NOTHING!!! WE ARE *NO* LAMERS. LET THAT BE CLEAR TO
> EVERYONE!!!!)... Good
> idea you might think. So I started f1-spirit in MSX4PC. I
> made a complete
> save state (that's where the emulator saves ALL information
> stored in the
> MSX)... What I then did was searching at which position of
> the save state
> file the VRAM started. Just trust me it was the good
> position. I'm 100% sure
> of that. What I then did was saving $4000 of data to a bin
> file which had
> this header:
>
> $0000, $3FFF, $0000 (last one unused for VRAM).
>
> After that I loaded that file on screen 2 in the VRAM again.
> F1-Spirit was
> created in screen 2 (also 100% sure). But the screen looked
> all scrambled.
>
> VRAM build up in screen 2:
>
> 0000H - 07FFH --> Pattern generator table 1
> 0800H - 0FFFH --> Pattern generator table 2
> 1000H - 17FFH --> Pattern generator table 3
> 1800H - 18FFH --> Pattern name table 1
> 1900H - 19FFH --> Pattern name table 2
> 1A00H - 1AFFH --> Pattern name table 3
> 1B00H - 1B7FH --> Sprite attribute table
> 1B80H - 1BAFH --> Palette table
> 2000H - 27FFH --> Colour table 1
> 2800H - 2FFFH --> Colour table 2
> 3000H - 37FFH --> Colour table 3
> 3800H - 3FFFH --> Sprite generator table
>
> But I didn't understand, because I had saved the first $4000
> bytes of the
> VRAM while f1-spirit was running, and I loaded it at the same position
> again. So I thought it would be ok, but it wasn't. So I
> searched for an
> explanation for that. After about a minute I thought I had located the
> problem. You can adjust all table addresses, so I looked in
> f1-spirit if
> they had done that, but they also didn't do that. What I then
> did was making
> a save state while the crap was on the screen. Then I
> compared that save
> state with the one of f1-spirit (at least that VRAM part
> ofcourse), and the
> two were identical! So I don't know what has gone wrong...
>
>
> So here's the situation.
>
> I have a file of $4007 bytes (inc. header) which will store itself on
> position $0000 of the VRAM.
> All table addresses are right.
> The screen lookes scrambled but the the VRAM data is identical.
>
>
> Can anyone help me with this problem??
>
> thank you.
> d-fader^TeddyWareZ
>
> PS. I just wanna state again that we don't want to have this data for
> stealing it... We just want to use it for our tests, because
> else we have to
> make the gfx first, and that takes time... We want this project to be
> finished as quickly as possible, because the game rules
> big-time... Please
> understand that...
>
> PS. And NO. Our game will not be in screen 2... ;)
>
>
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