Possible to "force" a game to run in MSX mode instead of MSX2?

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Door telecommand

Supporter (16)

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05-11-2019, 01:39

For example, I understand the MSX version of Xanadu is superior to the MSX2 version. If I have the cartridge version which is compatible with MSX and MSX2 and run it on an MSX2, can I make it run as though it was just an MSX? Or will it always boot in MSX2 mode and there's no way around it?

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Van sdsnatcher73

Hero (651)

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05-11-2019, 03:13

AFAIK the ROM version of Xanadu is an MSX1 game and although it has both an MSX and MSX2 logo it does not use any of the MSX2 features. Software companies put the MSX2 logo on it to show the game was compatible with those systems as well, as a way to show potential customers it was safe to buy if they had an MSX2. Not everyone with an MSX might be fully aware of the backwards compatibility in their system.

Anyway, there is some software that does indeed behave differently on an MSX2, like Nemesis 3. With a physical ROM or disk you would not be able to prevent the software to detect that it is running on an MSX2, but with software like SofaRun you could trick the software (ROM or Disk image) into MSX1 mode...

Van telecommand

Supporter (16)

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05-11-2019, 03:28

Oooooh well that answers that then thank you Big smile

Van Meits

Scribe (5644)

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05-11-2019, 11:08

Although I can not replicate it in openMSX and I do not have an MSX1 it is said that there is a tiny difference between the colors both generations output. The stories that some games look better on an MSX1 due to colors are not totally unknown to me, so that might be one.

Two might be the speed. At least in Basic the MSX1 is faster than any MSX after it (be it in z80/3.5MHz mode). How this translates to machine language, I don't know. Just a little while ago I ran Maze of Gallious on both a turbo R (in z80 mode) and a Philips MSX2. Booted both at the exact same time. After an hour they ran significantly out of sync with each other. And I mean really... I'd have to recheck it, but it was way more than half a minute.

So yes, you might experience differences between machine A and B

Van Grauw

Ascended (8508)

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05-11-2019, 11:20

In the case of Xanadu there are two versions: 1. a ROM version for MSX1, and 2. a disk version for MSX2. I forgot why, but I recall the MSX1 (ROM) version is superior (it certainly looks better, I think there were gameplay reasons as well).

Van PingPong

Prophet (3459)

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05-11-2019, 12:30

Grauw wrote:

In the case of Xanadu there are two versions: 1. a ROM version for MSX1, and 2. a disk version for MSX2. I forgot why, but I recall the MSX1 (ROM) version is superior (it certainly looks better, I think there were gameplay reasons as well).

Yes, the msx2 had a monochrome playfield.
Honestly i cannot figure why... If it was too much effort to create a decent background why they simply didn't reuse the msx1 one?
A Mistery.

Van NYYRIKKI

Enlighted (5396)

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05-11-2019, 13:45

Meits wrote:

Although I can not replicate it in openMSX and I do not have an MSX1 it is said that there is a tiny difference between the colors both generations output.

There must be something terribly wrong with your monitor. The difference on my laptop is very easy to see.

Here is combination of two screenshots of the palette from openMSX. The upper half is screenshot from MSX1 and lower half is screenshot from MSX2

Van Meits

Scribe (5644)

afbeelding van Meits

05-11-2019, 14:18

I used the palette info overlay using an MSX1 and an MSX2. There were no RGB deviations.

I should ofcourse checked the way you did, but I did not think of that. Neither did I expect that the palette info overlay would therefore deviate from what's shown on the actual MSX screen. Cuz if they're the same in the overlay but different on the MSX screen one of them is wrong and you just showed which... And that's the one I used to check.
Maybe something the openMSX guys could take a look at :)

Van Parn

Champion (424)

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05-11-2019, 15:05

Meits wrote:

Although I can not replicate it in openMSX and I do not have an MSX1 it is said that there is a tiny difference between the colors both generations output. The stories that some games look better on an MSX1 due to colors are not totally unknown to me, so that might be one.

Yes, they are different. They even differ from VDP model to VDP model, although in the case of the TMS VDPs the difference is smaller. The Texas VDPs uses YPbPr palettes which don't map perfectly to RGB, particularly limited 3-bit per component RGB like the V9938's, so Yamaha's engineers decided to change the palette anyway and make the colors more vivid.

Meits wrote:

Two might be the speed. At least in Basic the MSX1 is faster than any MSX after it (be it in z80/3.5MHz mode). How this translates to machine language, I don't know. Just a little while ago I ran Maze of Gallious on both a turbo R (in z80 mode) and a Philips MSX2. Booted both at the exact same time. After an hour they ran significantly out of sync with each other. And I mean really... I'd have to recheck it, but it was way more than half a minute.

Well, I would expect them to run out of sync since the Philips machine is 50Hz while the turboR is 60Hz by default. Unless your Philips has some kind of mod.

Incidentally, BiFi made a palette editor with some presets which try to approximate the MSX1 palette on a MSX2 or higher. There's even some game-specific presets which try to make some games look even better, like Shalom. It may be helpful:

BiFi's Palette Editor

You can even see a comparison between the presets here:

BiFi's Palette Editor Screenshots

Van sdsnatcher73

Hero (651)

afbeelding van sdsnatcher73

05-11-2019, 15:21

Actually on an MSX2 with SofaRun you can load one of several predefined pallets into the MSX2 (or higher) VDP and the game is then started with that pallet. One of them is the (close to) MSX1 pallet.

Van Meits

Scribe (5644)

afbeelding van Meits

05-11-2019, 15:46

Parn wrote:
Meits wrote:

Two might be the speed. At least in Basic the MSX1 is faster than any MSX after it (be it in z80/3.5MHz mode). How this translates to machine language, I don't know. Just a little while ago I ran Maze of Gallious on both a turbo R (in z80 mode) and a Philips MSX2. Booted both at the exact same time. After an hour they ran significantly out of sync with each other. And I mean really... I'd have to recheck it, but it was way more than half a minute.

Well, I would expect them to run out of sync since the Philips machine is 50Hz while the turboR is 60Hz by default. Unless your Philips has some kind of mod.

Both ran at 60Hz. If I kept the Philips at 50Hz the deviation would be way bigger after an hour.
It intrigues me enough to want to do a marathon videocapture of the computers I have here showing the same software on the same frequency/clock speed/processor mode.

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