Grauw’s RPG in development

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By ToriHino

Champion (348)

ToriHino's picture

11-08-2019, 21:26

Grauw wrote:

A programmable timer could be useful here! But alas, not available by default.

What kind of audio chips are you thinking about to support? The OPL4 has 2 programmable timers, but on the other hand it can take quite a few cycles to keep the OPL4 running.

By Grauw

Ascended (8311)

Grauw's picture

11-08-2019, 21:33

PSG + OPLL. And a sound chip should not be mandatory to play the game.

p.s. I just recalled I’m not in the DOS environment, so I can’t use RST Tongue.

By PingPong

Prophet (3413)

PingPong's picture

11-08-2019, 21:40

What environment are you using?

I do not understand why you cannot use rsts. Basically they are a lightweight form of call S. If you can install something at some address there should be no problem..... Or I m wrong?

By Grauw

Ascended (8311)

Grauw's picture

11-08-2019, 21:57

Just normal ROM cartridge environment. First 16K is occupied by the BIOS ROM, so I can’t write to the entry point. I am hesitant to switch it to RAM, it feels non-standard, could potentially cause compatibility issues and at least makes things more complicated just for the sake of a few cycles. I could use disk to ROM, but that would increase load times and not allow me to stream data to VRAM unless I require more than 64K RAM, while I want to run on any base spec MSX2+. So I like the DOS environment a lot but for this game I’ve chosen ROM.

By PingPong

Prophet (3413)

PingPong's picture

11-08-2019, 22:43

Do not know if this is possible. But maybe you could shadow the bios rom into a 16 k active ram area?
While I fully understand how ram paging works in general I found always a little obscure how slot mechanics works in msx....
Slots.... Mappers...... Expanded slot and hw placed in slots have been something a little obscure to be. Not to mention the xffff port on msx2 so maybe I m telling you bullshits in proposing to shadow and patch bios on ram as happens on turboR with basic

By ToriHino

Champion (348)

ToriHino's picture

12-08-2019, 00:50

Grauw wrote:

PSG + OPLL. And a sound chip should not be mandatory to play the game.

Yes, fair point. So this means you also support PSG only?

By Grauw

Ascended (8311)

Grauw's picture

12-08-2019, 01:25

That is TBD Smile.

Depending on whether I can find a cheap way to do it without completely rearranging the music.

By DarkSchneider

Paladin (854)

DarkSchneider's picture

12-08-2019, 10:11

Grauw wrote:

Just normal ROM cartridge environment. First 16K is occupied by the BIOS ROM, so I can’t write to the entry point. I am hesitant to switch it to RAM, it feels non-standard, could potentially cause compatibility issues and at least makes things more complicated just for the sake of a few cycles. I could use disk to ROM, but that would increase load times and not allow me to stream data to VRAM unless I require more than 64K RAM, while I want to run on any base spec MSX2+. So I like the DOS environment a lot but for this game I’ve chosen ROM.

Maybe you could use IM2? Not sure why is mentioned to be used by CP/M only, there is any impediment to put the table at #C000? Or the RST always points to page 0 for any IM?

By Grauw

Ascended (8311)

Grauw's picture

12-08-2019, 10:41

I do use IM2, but it indeed doesn’t affect the RST address (would’ve been nice, maybe).

By DarkSchneider

Paladin (854)

DarkSchneider's picture

12-08-2019, 11:50

That's nice. Then I would not bother too much about that as the benefit is not really great.

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