Did you know that Nemesis 3 is an "MSX2 game"?

Enlighted (6033)

20-12-2015, 16:23

Yeah, me neither... until today...

I remember people telling that Nemesis 3 works on their computer or that it doesn't work. I have not heard very many complaints from outside Finland, so I wanted to know a pattern for this behavior... This seems to be popular problem at least with Finnish/Swedish Spectravideo SVI-728 and SVI-738 computers.

It seems that on startup Nemesis 3 calls palette initialization routine (INIPLT) from SUB-ROM using EXTROM-call. As we know these are MSX2 only calls and on normal MSX1 this causes the CPU to crash after a while to RDSLT routine and exit gracefully after executing it. How ever in Finland we have PAL TV system and SVI-738 has V9938 VDP that boots to 60Hz mode after power on. Because of this there is an additional routine that switches to 50Hz mode on boot and the entry point is unfortunately right in the middle of this routine. The people who did Finnish localization did not want to have multiple versions to maintain, so this same MSX1 ROM has been used also on other MSX1 models.

So... If you have Finnish MSX1 you likely can't play Nemesis 3... Naturally this might effect also some other MSX1 models around the world, but at least you now know why. I have not investigated does this problem affect all versions of Nemesis 3.

By mars2000you

Enlighted (6432)

20-12-2015, 16:27

I think this has been fixed by BiFi : http://ips.tni.nl/rom/fixes-other/konami/fixes/RC764SVI.IPS

By NYYRIKKI

Enlighted (6033)

20-12-2015, 16:32

Not very helpful for a friend of mine, who just bought the cartridge, but good to know anyway.

By Daemos

Prophet (2051)

20-12-2015, 17:06

So its like a MSX 1,5 game?

By AxelStone

Prophet (3189)

20-12-2015, 18:26

Well not really a MSX2 game, it takes advantage of MSX2 palette. If you play in MSX1, the game works fine (at least in my MSX1 HB75P) but uses MSX1 palette. If you have MSX2, you get some imprevements as cycling color in fire planets of stage 1. It's not a big improvement, the game is almost the same that MSX1 version. In King's Valley 2 for example there exist 2 separate versions (MSX1 and MSX2) and the MSX2 version has clearly better graphics (SC2 vs SC5).

By hit9918

Prophet (2927)

20-12-2015, 19:21

it is an MSX2 game in terms of what bios version it needs.
for dirty reasons, it acidentaly works on most MSX1.

By anonymous

incognito ergo sum (116)

20-12-2015, 19:43

Both MSX logos (MSX and MSX2) are on the cover so it's an MSX1 game. Other thing is it fails in some MSX1 computers...

By RetroTechie

Paragon (1563)

20-12-2015, 19:50

PAC wrote:

Both MSX logos (MSX and MSX2) are on the cover

Yeah noticed that too... There's quite a few people who think it's an MSX2 game due to the excellent graphics, but I've always known it as MSX1 compatible.

Maybe Konami intented it that way, slipped up in the actual coding, but didn't catch the error before release?

By Pac

Scribe (6968)

20-12-2015, 19:59

After so many years, it's the first time I'm aware about problems of compatibility with this game as NYYRIKKI pointed out. Maybe it's only related to specific models, I have no idea.

By hit9918

Prophet (2927)

20-12-2015, 21:20

It calls an MSX2 bios function that does not exist on MSX1!
due to sheer luck, the garbage bytes of the typical MSX1 bios make it return.
or rather, bad luck for SVI user.
if the typical MSX1 had crashed right away, the thing would be discovered.

"it is an MSX2 game" was a headline for coders to smile

By raulsantacruz

Hero (604)

21-12-2015, 00:53

Probably Konami only test with Japanese MSX1 model, in the same way Konami don't (don't have to) test with Philips MSX2 models with the sound issues for their SCC chips ;D.