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PolestaR
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Some to codemaster interested people Some to VDP
 Posted: Sat Mar 10, 2001 4:11 am
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I've been doing a little testing with some roms. With F16 Fighter, after it enters TMS9918 graphics mode2 it writes 0x03 to VDP register 4. VDP register 4 on the TMS9918 is the pattern generator table (where the tiles are stored) but I dont think it is used as that on the SMS, though I could be wrong. Im thinking maybe it is used as the sprite doubler and 16x16 sprite settings, but I think only zoop could verify that. I'm not entirely sure what VDP register 3 on the SMS is used for in the TMS modes, but most directions point to the color table.
In regards to codemaster games I have got Micro Machines working pretty much perfectly (thanks to mikeG and Maxim for the rom). It doesnt seem to "abuse" the paging chip like Cosmic Spacehead which is some food for thought for the people who care (Zoop maybe). Since there are not too many active SMS emulator authors I think the only person who would be interested in the codemaster stuff would be zoop and he probably already trebles my knowledge on the subject, but if anyone else wants to know anything in particular or are having problems with getting the roms to work or something, just give me an email.
Spiderman return of the sinister 6 seems to write E0 to VDP register 14. I am not sure if this is correct or not as the rom doesnt seem to work on my emulator so maybe its just writing some rubbish into the VDP reg's, tho the rest of them look correct. Does anyone have any "special" information about Spiderman ROTS?
Thats about it.
-Jason Starr-
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- Joined: 14 Aug 2000
- Posts: 742
- Location: Adelaide, Australia
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Re: Entering mode 2
Posted: Thu Mar 15, 2001 6:16 am
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Quote > I've been doing a little testing with some roms. With F16 Fighter, after it enters TMS9918 graphics mode2 it writes 0x03 to VDP register 4.
how does the games actually enter mode 2? does it set some bits in registers 0 and 1?
VDP register 4 on the TMS9918 is the pattern generator table (where the tiles are stored) but I dont think it is used as that on the SMS, though I could be wrong. Im thinking maybe it is used as the sprite doubler and 16x16 sprite settings, but I think only zoop could verify that. I'm not entirely sure what VDP register 3 on the SMS is used for in the TMS modes, but most directions point to the color table.
Quote > In regards to codemaster games I have got Micro Machines working pretty much perfectly (thanks to mikeG and Maxim for the rom). It doesnt seem to "abuse" the paging chip like Cosmic Spacehead which is some food for thought for the people who care (Zoop maybe). Since there are not too many active SMS emulator authors I think the only person who would be interested in the codemaster stuff would be zoop and he probably already trebles my knowledge on the subject, but if anyone else wants to know anything in particular or are having problems with getting the roms to work or something, just give me an email.
> Spiderman return of the sinister 6 seems to write E0 to VDP register 14. I am not sure if this is correct or not as the rom doesnt seem to work on my emulator so maybe its just writing some rubbish into the VDP reg's, tho the rest of them look correct. Does anyone have any "special" information about Spiderman ROTS?
> Thats about it.
> -Jason Starr-
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PolestaR
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Re: Entering mode 2
Posted: Thu Mar 15, 2001 7:02 am
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Well from Charles Macdonalds doc, he says there are all the original TMS9918 modes on the Master System (ie Mode1,Mode2,MultiColor and Text Mode) but Im not entirely convinced this is the case. I think possibly only MODE2 is included since most Sg1000 games used this mode and its the only decent mode the TMS9918 has anyway.
How does a SMS game enter mode2? Well usually BIT2 of VDP reg 0 is set, this seems to specify that we want the SMS mode. When it is clear we stop using SMS modes and switch the MODe2. The funny thing is, the *only* difference between F16 fighter and another game being in different graphic modes is this ONE BIT switch. CHarles document talks about their being 3 TMS mode bits, but I think he has this wrong. As all SMS games set TMS MODE3(or MODE1 i forget). THe other two mode bits are just used to stretch the screen, from 24 rows to 28, and from 24 rows to 30 and are just to do with the Master SYstem graphics modes. Hopefully more investigation in this area will provide some more solid results/answers. Hope ive helped.
-Jason Starr-
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PolestaR
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BTW>..
Posted: Thu Mar 15, 2001 7:03 am
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Find me a Master SYstem 1 and I'll get someone to pick it up for me!!!! Thanks :P. YOu live in adelaide right?
-Jason Starr
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- Joined: 21 Apr 2000
- Posts: 598
- Location: Newcastle upon Tyne, England
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Re: Entering mode 2
Posted: Thu Mar 15, 2001 7:27 am
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Quote > Well from Charles Macdonalds doc, he says there are all the original TMS9918 modes on the Master System (ie Mode1,Mode2,MultiColor and Text Mode) but Im not entirely convinced this is the case. I think possibly only MODE2 is included since most Sg1000 games used this mode and its the only decent mode the TMS9918 has anyway.
Hmm... can you think of a SG-1000 game that doesn't use mode 2? If so, I'll try it on the Master System to see if it works. All the SG-1000 games I've tried so far have been fine, but I have no idea which modes they use.
Mike
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PolestaR
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Re: Entering mode 2 million
Posted: Fri Mar 16, 2001 12:51 am
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I cant remember where my original post to this question went. I did it last night but it didnt seem to update.
Anyways POP FLAMER.sg seems to not use MODE2 so you could try that game. Would be interesting to see if it worked or not!
-JAson STarr-
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- Joined: 14 Aug 2000
- Posts: 742
- Location: Adelaide, Australia
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Re: SMS 1
Posted: Fri Mar 16, 2001 6:43 am
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adelaide is my residence. i saw a sms1 only for $5 and one with hooks and etc for 10 or 15 if i remember correctly. i was contemplating getting it myself. i have to see whether it still is available, but sms1s turn up all the time. i'll email you when i have info jason.
a s out.
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PolestaR
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Great!! Look forward to it *nt*
Posted: Fri Mar 16, 2001 7:27 am
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Quote > adelaide is my residence. i saw a sms1 only for $5 and one with hooks and etc for 10 or 15 if i remember correctly. i was contemplating getting it myself. i have to see whether it still is available, but sms1s turn up all the time. i'll email you when i have info jason.
> a s out.
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Kroustibat
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Re: Entering mode 2 million
Posted: Fri Mar 16, 2001 11:32 am
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Quote > I cant remember where my original post to this question went. I did it last night but it didnt seem to update.
> Anyways POP FLAMER.sg seems to not use MODE2 so you could try
yep, popflamer user mode 1 as Championship baseball and champion golf
that's the only one i'm aware n
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- Joined: 21 Apr 2000
- Posts: 598
- Location: Newcastle upon Tyne, England
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Pop Flamer works...
Posted: Fri Mar 16, 2001 8:28 pm
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Quote > I cant remember where my original post to this question went. I did it last night but it didnt seem to update.
> Anyways POP FLAMER.sg seems to not use MODE2 so you could try that game. Would be interesting to see if it worked or not!
Well I tried Pop Flamer and it works on both the SMS 1 and SMS 2, as do the two games that Kroustibat mentioned (Champion Baseball and Golf), so the mode they use is definitely supported by the SMS.
Mike
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PolestaR
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Re: Pop Flamer works...
Posted: Sat Mar 17, 2001 7:26 am
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Interesting! Thanks Mike, I guess the vdp registers must still be arranged so that the old TMS games can use them just like the new features werent even present. Thanks again.
-Jason Starr-
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