BLOADing a game from Basic...

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Par cesco

Champion (453)

Portrait de cesco

03-03-2008, 16:20

I'd like to load "Chaos Begins" on my old Philips VG-8020... so I started thinking that I could split the 32Kb ROM in two binary files and BLOAD them from MSX Basic. But then I have realised that I can't do that Sad

The problem is that "Chaos Begins" requires to be loaded from the starting address &h4000, and that address is not available under MSX Basic (because from what I have understood a large portion of memory around that area is reserved); and of course I can't use an application like ODO or LOADROM because I don't have a floppy drive on my VG-8020.

What could I do in order to get that game working ?

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Par hap

Paragon (2042)

Portrait de hap

03-03-2008, 18:13

Did you try Waver?

Par ARTRAG

Enlighted (6923)

Portrait de ARTRAG

03-03-2008, 18:15

You need two ASM "relocators" to be placed in RAM

You should split the rom in two files of 16K and load the two pieces in two times
using two different relocators

The relocator of piece 1 has to look for RAM in slots, at page 1
enable the ram from $4000-$7FFFF
LDIR the first piece in that page
switch back to basic rom and return

The second relocator has to
LDIR the second piece in page 2 from $8000
(the trick is that part of the ROM will overlapped the start of
the second piece, but who cares, what you loose
has been already copied to its correct position),
enable the same slot in page 1 as above
enabling the ram from $4000-$7FFFF where the piece 1 was
jump to the start of the ROM (the address in its header)

Par Guillian

Prophet (3516)

Portrait de Guillian

03-03-2008, 23:00

Another option is to order a copy of the game in cartridge Wink

Par Vincent van Dam

Hero (513)

Portrait de Vincent van Dam

03-03-2008, 23:17

Is it available on cartridge already?

Par anonymous

incognito ergo sum (116)

Portrait de anonymous

03-03-2008, 23:25

That's, for sure, the best option, Guillian. I will properly announce the release of the Caos Begins cartridge here on the forums later.

Cesco, I am not sure... did you sent me an email this morning? (well, I am the programmer of Caos Begins) If your goal is to run Caos Begins on your MSX, then some tool to generate a WAV is a good choice. I guess you are working on MSX Taper, isn't it?.

If your goal is to build the tool to load the game, then let me know if you need more information. I think ARTRAG pointed you to the right way.

But... of course... the best best of the best ways to play Caos on a real MSX is, undoubtedly, the cartridge version. Indeed. Smile

Par cesco

Champion (453)

Portrait de cesco

04-03-2008, 13:29

You need two ASM "relocators" to be placed in RAM

Thanks for the hints; I guess that the best thing I can do in this moment is to have a look at the source code of CASLINK. Some weeks ago I got the permission from Alexey Podrezov to use the ROM loader he wrote, maybe it's time to start making a good use of that permission.

Par cesco

Champion (453)

Portrait de cesco

04-03-2008, 13:43

Cesco, I am not sure... did you sent me an email this morning? (well, I am the programmer of Caos Begins)

Yes, that was me

If your goal is to run Caos Begins on your MSX, then some tool to generate a WAV is a good choice. I guess you are working on MSX Taper, isn't it?.

If your goal is to build the tool to load the game, then let me know if you need more information. I think ARTRAG pointed you to the right way.

Yes, thank you so much Smile

Par cax

Prophet (3740)

Portrait de cax

04-03-2008, 14:40

You can also try MicroWAVer, which can compress ROM and convert it to single self-extracting BIN, if the ROM compresses well. And even if it doesnt - you still get bloadable WAV.

Par jltursan

Prophet (2619)

Portrait de jltursan

05-03-2008, 10:41

I've found a bunch of useful relocating routines in the MSX Top page. Go to download section and look for "init games" routines.
There're no sources; but being so small it doesn't matters...

Par cesco

Champion (453)

Portrait de cesco

05-03-2008, 10:58

You can also try MicroWAVer, which can compress ROM and convert it to single self-extracting BIN, if the ROM compresses well. And even if it doesnt - you still get bloadable WAV.

Thank you Cax, I used a lot MicroWAVer together with WAVer in the past, but I think that I should take this opportunity and try to perfect MSX Taper (and trust me, that is a VEEEEEEEEERY LONG WAY Wink )

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