New SegaCD Region Converter

Mask of Destiny

New Member
Get it here: http://www.pages.drexel.edu/~mrp29/convscd.zip

The program should have much better luck doing the folowing conversions than scdconv:

EU -> US

Jap -> US

Jap -> EU

There are only a few instances when it will fail at these conversions:

1)The main processor and sub processor boot code are highly timing sensitive because they don't handshake properly

2)The game actually goes and checks the region of the console itself

3)It's an NTSC game that can't cope being on a PAL machine or vice versa

4)The boot code takes up all 16 sectors alotted to it by the ISO

It's theoretically possible to fix 1 and 4, but it's a lot of extra work and I don't think it will be an issue. I do know that 2 is an issue for 1 or 2 games and 3 will probably be an issue with FMV games and possibly games that use RasterF/X.

Anyway, it would be nice if people could report back when they convert games and tell me how it went so I can make a compatability list.
 

mal

Member
Originally posted by Mask of Destiny@Sep 8, 2003 @ 09:55 AM

There are only a few instances when it will fail at these conversions:

...

4)The boot code takes up all 16 sectors alotted to it by the ISO
I was under the impression that this was the main problem with SCDconv as well
 

Mask of Destiny

New Member
Originally posted by mal+Sep 8, 2003 @ 01:33 AM--><div class='quotetop'>QUOTE(mal @ Sep 8, 2003 @ 01:33 AM)</div><div class='quotemain'> <!--QuoteBegin-Mask of Destiny@Sep 8, 2003 @ 09:55 AM

There are only a few instances when it will fail at these conversions:

...

4)The boot code takes up all 16 sectors alotted to it by the ISO
I was under the impression that this was the main problem with SCDconv as well [/b][/quote]

The main problem with converting Sega CD games is the way the code on the main processor is loaded and the fact that the security codes aren't the same size. The game code is right after the security code, so if you change the size of the security code, the game code moves around in memory. Most machine code does not behave correctly when it's moved in memory.

If the security code from the source region is larger than the destination region the solution is simple. You either fill the extra space with nops or us a branch instruction to skip over the gap. This works with the following conversions:

US -> Jap, US -> EU, and EU- Jap.

IIRC, these are the conversions scdconv is good at. Doing the other six conversions takes a little more work and I've come up with a solution that should work in most situations. scdconv has close to a 100% failure rate on these other three conversions which leads me to believe that it does not play any special tricks.

I suppose there's no way to tell for sure until someone tests this new tool to see if it performs better. I do know that it works with Smurfs (E), though the FMVs are desynced.

Does anyone have a link to the scdconv compatability list?

EDIT: Nevermind. I found it myself.

Also upon looking at the scdconv readme, my suspicions are confirmed.

However, I will give NO GUARANTEE FOR SUCCESS of the conversion,

because there might be some games which don't have relocatable

code (which this program assumes).
and

The reason for the different success rates lies in the special design

of the Sega CD games' boot blocks. Unfortunately, Sega decided to mix

security code and actual game code in the first few sectors, which

makes it very difficult (in most cases) to relocate the game code in

order to gain space for the lengthy American and European security

codes. If a game doesn't use relocatable code (as it is theoretically

a Sega programming standard), the conversion might fail.
 

Tindo@heart

New Member
whoop? I was just about to say I'm burning a converted copy of the Smurfs, and I think it should work. but I read that you have tried the Smurfs.

However, while running to program it was a little buggy.

I Pressed "1" to select a US destination.

It detected it as a "jap" game, and offered me 4 selections:

1-Yes

2-No, it should be US

3-No, it should be EU

4-No, it should be JAP

I picked "3", but it started the converstion as a

JAP>US

?

The converstion didn't work.

I ran it again, and picked 1. also didn't work.

I picked 2, and it correctly converted from:

EU>US

I think the 3 and 2 selections are backwards on the program?? I dunno.

*goes to burn Smurfs* :)
 

Tindo@heart

New Member
:banana

Yahoo! The smurfs now work on my US region SegaCD!!

Thanks a lot!! I've been waiting for this.

I've played through the first 2 levels of the Smurfs, and it plays fine. This seems like a pretty fun game too!
 

Area-51

New Member
got the smurfs to convert just like above...

it is buggy.

tried to convert jap game to no avail.

3x3 Eyes
 

Mask of Destiny

New Member
Originally posted by Area-51@Sep 9, 2003 @ 01:07 AM

tried to convert jap game to no avail.

3x3 Eyes
I found a little problem in the way I handle a couple of the values in the header. If I have time I'll post a new version of the program tomorrow. Hopefully it will get that game working.
 

Area-51

New Member
OK, I did some tests, these were tested only on Gens 1.9 after region conversion was done using Convscd 1.02.

Will have to burn and verify if they work properly on actual SCD unit.

3x3 Eyes Converted from JP to US, didn't work

:D After Armageddon Converts from JP to US, works fine

:D Cyborg 009 Converts from JP to US, works fine

:D Baku-Den Converts from JP to US, works fine

Earnest Evans Converted from JP to US, didn't work
 
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