What is the sense of transforming games to MMC5?

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Diskover
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What is the sense of transforming games to MMC5?

Post by Diskover » Sat Aug 17, 2019 12:09 am

I have been observing a user who hangs patches to pass UNROM games to MMC5 in Romhacking for a few days.

I don't understand what the meaning of this is.

Is there any practical, visual, or improvement advantage?

EJ: https://www.romhacking.net/hacks/4642/

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Bregalad
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Re: What is the sense of transforming games to MMC5?

Post by Bregalad » Sat Aug 17, 2019 1:03 am

There's absolutely no sense in doing that if nothing else than the mapper is changed.

I guess this is meant as an hacking exercice, and they pick the MMC5 because they have a feel of "powerfulness" or something like that. This is straight idiotic.

Mapper hacks, however, makes sense if :
  • You're using a flashcard that doesn't support the original mapper (in the case of the MMC5, it's one of the least likely mapper to be supported by flashcards, so this makes no sense)
  • You're actually translating or hacking the game, and needs extra features the original mapper lacks (for instance, more ROM)

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koitsu
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Re: What is the sense of transforming games to MMC5?

Post by koitsu » Sat Aug 17, 2019 3:55 am

These are the only details I could find based on that page and readme:
Expansion RAM ($5C00-$5FFF, read/write) CPU $6000-$7FFF: 8 KB switchable PRG RAM bank Bankswitching included. Readme file for more info. Extended RAM mode ($5104)
Top Gun Mapper Conversion
From UNROM to MMC5 (from UNROM to Mapper 5)
by Dracula X

RELEASE DATE: August 15, 2019
TIME SPAN FROM START TO FINISH: 1 Day

Bankswitch:
To use it, all you have to do is select a bank and jump to it.

LDA bank_number
JSR $FFB0

You can also use Nflate from http://www.romhacking.net/ Utilities to expand the ROM up to 512kb.

You can now use free RAM space at $5c00 to 5fff and $6000 to $7fff for cool or new stuff.

Bankswitching:
to bankswitch from $8000 - $Bfff and from $C000 - $ffff, here's how to do it:

LDA bank_number
JSR $FFB0
JMP New Location

or

LDA bank_number
JSR $FFB0
RTS

New location would be $8000 or $A000 etc... Bank 08 would be at $20010.

Credits:
Rockman: for info on how to convert the mapper!
Disch: for his mapper docs!

Have fun!

This patch only works for:
US Revision 0
US Revision 1

This patch does not work for:
Japan Version
Europe Version


Non Supported Emulators:
Nintendulator
RockNES
VirtuaNES
Opinion (though you didn't ask for it directly): this is someone trying to make a name for themselves and get attention. This has happened for decades in the romhacking community, and in old days, the more senior/experienced folks would usually "weed out" these people in chat channels because they brought nothing to the table. On the flip side, this at least means the guy can do some assembly work, which means he/she'll be sought after in the romhacking community (graphics hackers are in abundance, script hackers are somewhat in abundance, but the people who do the underlying RE and assembly work and know what they're doing are still rare. That fact is actually what made the SD3 romhack/translation so memorable/remarkable -- Neill Corlett does very, very good work.)

While switching games to a different mapper *is* an involved process and I respect that work (honest!), in this case -- based solely on the above info -- there seems to be no actual goal other than "look mum, I did something".

That said: if this is a stepping stone for the romhacker to begin doing more extensive romhacks of Top Gun (and maybe use MMC5 features?), then THAT is something worthwhile -- and I do hope that is the goal. (I always liked Top Gun more than Top Gun 2.)

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Dwedit
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Re: What is the sense of transforming games to MMC5?

Post by Dwedit » Sat Aug 17, 2019 10:02 am

The only real use I can think of is that another rom hacker could use that as a base for a more complicated romhack, as the mapper hack was already done.
Here come the fortune cookies! Here come the fortune cookies! They're wearing paper hats!

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Bregalad
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Re: What is the sense of transforming games to MMC5?

Post by Bregalad » Sat Aug 17, 2019 1:51 pm

Dwedit wrote:The only real use I can think of is that another rom hacker could use that as a base for a more complicated romhack, as the mapper hack was already done.
Sure, but if you are able to put a real use of the MMC5 in your ROMhack then you're definitely able to do the mapper hack by yourself, as such you don't need the original guy who only modified the game to use MMC5 instead.

Diskover
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Re: What is the sense of transforming games to MMC5?

Post by Diskover » Sun Aug 18, 2019 5:23 am

Thanks for the answers.

Yes, the first idea that came to me was that then someone can do another hack taking advantage of the transformation to MMC5.

kuja killer
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Re: What is the sense of transforming games to MMC5?

Post by kuja killer » Thu Aug 22, 2019 2:05 pm

I once made a MMC5 conversion for Rockman 5 years ago (not megaman 5) here:

https://www.romhacking.net/hacks/1387/

my real intention for doing this was i wanted to see it ...just once.. be used in someone's own new Rockman 5 romhack, them hopefully taking advantage of the extra programming space for example.

688 downloads, but..
I've never seen anyone use it though. :( Or found a hack "in the wild" using the mmc5

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Banshaku
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Re: What is the sense of transforming games to MMC5?

Post by Banshaku » Thu Aug 22, 2019 5:58 pm

@kuja killer

Wasn't Mega Man Odyssey a romhack you worked on that needed to port an existing engine to mmc5 then used its extra features (unless I'm mixing with someone else?).

In that case, this is a very good example to convert an existing game to MMC5 when you actually uses it features :D

kuja killer
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Re: What is the sense of transforming games to MMC5?

Post by kuja killer » Fri Aug 23, 2019 12:33 am

yea my game uses mmc5 and all the abilities and stuff for mmc5 as much as possible. I use pretty much everything there's known, "except" the vertical screen split thing.

There's no way this could ever be used for a base mm3 hack because far far too much has been changed over the years. Literally next to zero stuff remains in the original megaman 3 except music engine and physics. But it's all still edited so much like everything re-wrriten to use less code/less lag and so on.

Music engine does have edits too, to actually allow using the 2 extra square channels the MMC5 has, for both sound effects and music. It has not officially been used to this day yet for any songs. But i hope one day a song will use them.
The only place so far is the Item Shop song, which uses the 2 mmc5 squares and "not" the regular NES ones... so that the cursor sound effect does not get cut off ...or vice versa something

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Banshaku
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Re: What is the sense of transforming games to MMC5?

Post by Banshaku » Fri Aug 23, 2019 11:11 pm

I see. I'm more of a dev so for now romhacking is not in my skill set :lol: I find it impressive how people can reverse engineer the rom and add things to it. Always amazed by it.

I will try to not derail the thread too much (since when on nesdev we don't derail threads anyway :lol:) but how is your romhack going? Didn't check in a while so I'm curious to know what is new since I have interest in mega man on the nes in general ;)

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Sumez
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Re: What is the sense of transforming games to MMC5?

Post by Sumez » Thu Aug 29, 2019 4:19 am

IIRC MMC5 was the only "official" (or at least most popular) mapper chip that would support ROM sizes of 1MB, so in the context of romhacks, maybe a MMC5 hack is intended to leave the game open for crazy hacks that require a lot of extra space?

kuja killer
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Re: What is the sense of transforming games to MMC5?

Post by kuja killer » Thu Aug 29, 2019 2:04 pm

yea totally because rockman 4 MI is 1 MB, mm4 was CHR-RAM ..so that was not changed at all, so no graphics, but 1 full MB of code though.

The mmc3 rom of 4 mi is also 1 MB (no graphics cause of chr-ram) ...i dont understand how he did that though, i thought max was 512 kb for mmc3.
no emulators work with it. fceux, bizhawk, nintendulator, nestopia all crash ...but according to his readme (japanese) other emulators apparently DO work, to some degree....

I personally use 512 KB graphics and 512 KB code so far on my game. I have "not yet" had to upgrade either one since starting this hack. Though i am starting to get close though on having no room left for code. (about probably 3 2000-byte banks remaining)

aquasnake
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Re: What is the sense of transforming games to MMC5?

Post by aquasnake » Sat Sep 14, 2019 12:09 am

Sumez wrote:IIRC MMC5 was the only "official" (or at least most popular) mapper chip that would support ROM sizes of 1MB, so in the context of romhacks, maybe a MMC5 hack is intended to leave the game open for crazy hacks that require a lot of extra space?
modified MMC3(m74, m245...) can support PROM up to 2 mega-bytes

so i dont think its meaningful,whatever running in emulator or to make a real cart

aquasnake
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Re: What is the sense of transforming games to MMC5?

Post by aquasnake » Sat Sep 14, 2019 12:21 am

aquasnake wrote:
Sumez wrote:IIRC MMC5 was the only "official" (or at least most popular) mapper chip that would support ROM sizes of 1MB, so in the context of romhacks, maybe a MMC5 hack is intended to leave the game open for crazy hacks that require a lot of extra space?
modified MMC3(m74, m245...) can support PROM up to 2 mega-bytes

so i dont think its meaningful,whatever running in emulator or to make a real cart
the only purpose to transfer to mmc5 i think is that hacker he is the one having the ability to design a clone mmc5 chip, and to prevent the rom being pirated twice or more, so he can sell his cart monopoly


:)

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