On Tue, 16 Mar 1999, Maarten ter Huurne wrote:
> At 02:40 PM 3/15/99 -0300, you wrote:
>
> >> And ROM pages are 8K in size, mapper pages 16K. This means that sometimes
> >> you need to duplicate ROM pages in the mapper to allow all combinations
> >> used by the game. Example: ROM page 0 and 4 are used together, just as ROM
> >> page 0 and 13. In the mapper you'll need 2 pages (32K) for those three 8K
> >> pages (24K).
> >
> >If you have 256kb of RAM, there's enough space to do all the necessary
> >combinations. Or am I wrong?
>
> It depends on the game. In theory, it could use 16 * 16 = 256 combinations
> of two pages. That would require 4MB RAM. But in practice, only a very
> small amount of combinations is actually used. 256K should be enough to
> contain all combinations in 95% of 128K ROMs.
Right, I was thinking in Konami games, that demands that only the block 0
be combined with blocks 4, 7, 10 and 13 (for 128kb games).
> >> Many MSX2 games use only 64K VRAM. Firebird and King's Valley 2 are >>
> examples.
> >
> >Ok, but VRAM needs to be copied to RAM. If you need to copy data, you can
> >transfer RAM to RAM and make the necessary block combinations with LDIR.
>
> Yes, RAM to RAM copy is preferable, _if_ you have enough RAM available.
Ok, I didn't know that Memory Mapper of 128kb existed. But does someone
have an MSX2 with 128kb of VRAM and only 128kb of Mapper?
> >I have never seen a MSX2 with less than 128kb of VRAM.
>
> Neither have I.
> But for example Hydlide 1 checks for 64K or 128K VRAM and displays a
> different loading picture for both cases.
Where can I download the entire Hydlide series? Funet?
Beyond Metal Gear 2, do you know other Megarom games with 512kb of more?
Greetings from Brazil!
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