UMDK, documentation, tutorials and general knowledge.

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Montserrat
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UMDK, documentation, tutorials and general knowledge.

Post by Montserrat » Fri Dec 04, 2015 10:49 pm

Hi all, some of the test-run kits are starting to work (using some tricks and workarrounds) think its time of having a "how to" and general knowledge about how to operate the kit.

Since im a dummy, i dont have even a programming background (yes, i know...thats hardcore to start lol),the first thing i've tried is to replicate what Chris did in her UMDK video. Hacking the sonic1 rom to give sonic infinite lives.

Obviusly he's using DDD a debugger program that shows the MD machine code thanks to UMDK. To be able to make that sonic hack (and work with UMDK) i need to learn how to use DDD, i've found the official documentation here:

http://www.gnu.org/software/ddd/manual/ ... o/ddd.html

I'ts a nicely done doc, but i miss some tutorials...do you have other nice documentation or tutorials?

prophet36
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Re: UMDK, documentation, tutorials and general knowledge.

Post by prophet36 » Fri Dec 04, 2015 11:22 pm

Montserrat wrote:i dont have even a programming background
Truthfully, without any programming experience, you will find it difficult to do anything useful with your UMDK cart. I recommend learning C, and using the gcc compiler on your Linux machine (the native x64 compiler, not the 68000 cross-compiler you built during UMDK setup), and using ddd to step through your code. It will take you at least a few months to learn the basics of C, then you could start to learn 68000 assembly-language. I wouldn't bother learning x64 assembler, it's very complex compared with the relatively simple 68000, and it will probably just confuse you. I guess what I'm saying is that there are no short-cuts. I learned 68000 assembler and C in 1989, and I'm still learning new things about them. As I mentioned right at the start, UMDK is not intended to be a beginner project.

Montserrat
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Re: UMDK, documentation, tutorials and general knowledge.

Post by Montserrat » Sat Dec 05, 2015 12:23 am

Im in a diferent aproach. I know assembly its not meant for novices.

But im making all of this as a "revival" hobby, back then they used assembly (also C in the final days of MD) to code in the megadrive, and i want to recreate that era, we all do this for some reason, some for curiosity, some for nostalgia, others to show what they are capable of. I do for fun and want to feel that era of creativity at the lowest level...they worked with so little resources and did so much awesome games...

Theres a ton of megadrive developers back then that did not have a clue of computers and they did learn, i want to do so. Everyone has his own motivations, most people would already given up, and vomit lol...i just keep doing one more step.

Noobs like me need some entry level motivation, thanks to BigEvilCorporation i realized that i can undestand how the megadrive works, and thanks to that we can "mass" produce the UMDK now (when it's fully working). Even me at 1/10 coding skills can contribute somehow.

For me the UMDK is a way to do changes on the fly on my code, like the infinite lives you did in sonic, thats all i need at the moment, ill have time for learning advanced stuff...

prophet36
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Re: UMDK, documentation, tutorials and general knowledge.

Post by prophet36 » Sat Dec 05, 2015 12:55 am

Montserrat wrote:and thanks to that we can "mass" produce the UMDK now (when it's fully working). Even me at 1/10 coding skills can contribute somehow.
And you have done an awesome job there. You have every reason to be proud of yourself. And I apologise if I have dampened your enthusiasm.
Montserrat wrote:the infinite lives you did in sonic, thats all i need at the moment, ill have time for learning advanced stuff...
I dunno, I think the process I went through in the video (compare memory-dump before and after Sonic dies to find the address of the life-counter variable, then search through the trace-log to find the address of the code in ROM that decrements that variable, then work out which opcodes to replace in the ROM to get infinite lives) is pretty advanced stuff. Conversely, the process I suggested in the other thread for testing the flash was comparatively straightforward, but it just came out intergalactic. I guess my problem is I (evidently!) find it difficult to make my explanations easy to understand. I'm not being arrogant or facetious, I'm just not a very good teacher.

MintyTheCat
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Re: UMDK, documentation, tutorials and general knowledge.

Post by MintyTheCat » Tue Dec 15, 2015 9:46 am

Montserrat wrote: http://www.gnu.org/software/ddd/manual/ ... o/ddd.html

I'ts a nicely done doc, but i miss some tutorials...do you have other nice documentation or tutorials?
This book is more like a tutorial on GDB:

http://www.amazon.co.uk/Art-Debugging-G ... ds=ddd+gdb

I refer to it sometimes when I forget how to do something.
UMDK Fanboy

Montserrat
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Re: UMDK, documentation, tutorials and general knowledge.

Post by Montserrat » Thu Dec 17, 2015 12:59 pm

Thanks! nice docs!

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