#113716 - Nicolas - Fri Dec 29, 2006 11:20 pm
Hello,
I was searching today for informations about the Gameboy internals and I discovered the wonderful gbspec.txt file. I was wondering where do the informations it contains come from (reverse-engineering? Nintendo? (If so, are the original documents available?)). As I was unable to find the information on the web, I hope someone here will be able to tell me.
Thanks a lot.
Regards,
Nicolas
#113729 - keldon - Sat Dec 30, 2006 2:02 am
gbspec.txt, oh my gosh that brings back memories. I first printed that out donkey years ago during work experience but I don't have a copy anymore.
Martin Korth is the guy behind nocash; and if you go to the nocash_gameboy site there is an updated html version of the gameboy pandoc.
#113818 - Nicolas - Sun Dec 31, 2006 12:31 am
Thanks keldon for your answer. But do you know where do the original informations gbspec.txt (or gbadev) contains come from? Mainly from developers who had access to the official documentation or from reverse-engineering?
Thanks again
#113821 - keldon - Sun Dec 31, 2006 12:46 am
Experimentation with hardware. Maybe some people believe there was a look at official documents; but undocumented features are listed - which leads me to believe that developers informed Martin Korth that features and information not documented by Nintendo featured in the pandoc.
Once the XBoo cable was created it was possible to run code on the gameboy without the need for a cartridge. Plus you have to remember that the processor is nothing special so code will always be created; it's just a case of finding the hardware!
#113823 - Nicolas - Sun Dec 31, 2006 1:19 am
Thanks! :-)
#113826 - tepples - Sun Dec 31, 2006 2:42 am
| keldon wrote: |
| Once the XBoo cable was created |
Were any trade-secret documents necessary to get to the point where the XBoo cable could be created?
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.
#113831 - keldon - Sun Dec 31, 2006 3:15 am
| tepples wrote: |
| keldon wrote: | | Once the XBoo cable was created |
Were any trade-secret documents necessary to get to the point where the XBoo cable could be created? |
I was just pointing out that much more experimentation could take place with the XBoo cable without the need for any additional hardware. Trade secret documents are not needed to reach that state; a gameboy can boot from the serial cable! Once you have created the cable you can experiment using the information you know. If you dump data sent from another gameboy then you will also get code that alters VRAM and give you access to information on how to configure the gameboy.
#113834 - tepples - Sun Dec 31, 2006 3:55 am
| keldon wrote: |
| tepples wrote: | | keldon wrote: | | Once the XBoo cable was created |
Were any trade-secret documents necessary to get to the point where the XBoo cable could be created? |
I was just pointing out that much more experimentation could take place with the XBoo cable without the need for any additional hardware. Trade secret documents are not needed to reach that state; a gameboy can boot from the serial cable! |
But did it take trade secret documents to learn how to make the serial cable (and, in the case of 8-bit Game Boy systems, the cartridge that drives the client side of the serial cable)? How did reverse engineers get from 0 to serial cable?
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.
#113848 - keldon - Sun Dec 31, 2006 10:48 am
I would think that the xboo cable would fairly simple to figure out; the GB serial controller could still be carried out without knowing how the gameboy works.
What puzzles me is how other information was figured out, such as alternative opcodes; without documentation you run the risk of causing damage. Although if you sacrificed your gameboy you could probe its processor using additional hardware!
p.s. my mistake on names, xboo is the parallel cable for the gba
#113850 - Dwedit - Sun Dec 31, 2006 11:58 am
Since when can the GB run code fed to it from a serial cable? The only way it could do that would be if there was a cartridge in the slot waiting to receive code, copy the code to RAM, and execute that code.
_________________
"We are merely sprites that dance at the beck and call of our button pressing overlord."
#113859 - keldon - Sun Dec 31, 2006 2:48 pm
| Dwedit wrote: |
| Since when can the GB run code fed to it from a serial cable? The only way it could do that would be if there was a cartridge in the slot waiting to receive code, copy the code to RAM, and execute that code. |
My mistake; I was searching for documentation but I cannot remember much of how things were done on the GB in terms of getting it to run on hardware. I used to compile and run everything in nocash as I never had the money for hardware.