[EMAIL PROTECTED] am 05.07.98 18:48:00

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An:    [EMAIL PROTECTED]
Kopie:  (Blindkopie: Wolfgang Oberleithner/ISOVOLTA/AT)
Thema: Re: Hooks



>    There is a faster way to redefine all three pattern tables at the
>same time in SCREEN 2.
>
>    You can just do a VDP(4)=0. This command enable a undocumented
>feature of MSX-1: SCREEN 2 with only one pattern table!! You still have
>three color tables, but this also can be changed with a VDP(3)=&h9F.
This sounds very similar to the ReAdressing I use in my programs.
Check the technical databook of the VDP. To each screen you have
values for the Registers which can be changed to get a different
starting adress for some VDP-parts.

Take a register, look at the bits-definition,
for example:     0   0   0   A15  A14  A13   1   1

If you set the "MUST"-bits (1) to zero, the range of the
vram-area is divided by two. That means:
0 1 at the end: half the range
0 0 at the end: quater the range...

This one is based on a theory of mine, but it works! If anyone can
correct it - pls do so...


>    I'm not sure if this works in all MSXs. It works fine on my Expert
>1.1, and it was tested in MSX2+ and T-R GT with success. But some tests on
>the Turbo-R ST failed. Maybe someone out there with T-R ST could test it
>and tell the results?
Obove mentioned things work on my modified 2+ and I think on the tR too...

greetz

wolfgang






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