GB BIOS mapping

Discussion of programming and development for the original Game Boy and Game Boy Color.
Post Reply
mudlord
Posts: 14
Joined: Sat Jun 12, 2010 8:05 pm
Contact:

GB BIOS mapping

Post by mudlord » Sat Nov 20, 2010 6:46 pm

Hi,

I have a question about the *normal* GB BIOS, not the GameBoy Colour (which was documented on Costis's page along with his dump)

I am not sure on how the GB BIOS is mapped into RAM. According to Costis's page...
Costis wrote:The boot ROM is mapped in the GB address space from 0×0000 to 0x00FF and from 0×0200 to 0x08FF. In the binary file above, I have filled the space from 0×0100 to 0x01FF with 00′s which is where the external ROM data normally would be (from the cartridge header.
Which makes sense for the GameBoy Colour. I am just unsure if the normal GB BIOS, which was dumped by nevitski uses the same mapping, since there seems to be no docs out there at all for the GB BIOS (and Martin's docs in that regard are extremely vague and non existant).

Thanks.

User avatar
Dwedit
Posts: 4251
Joined: Fri Nov 19, 2004 7:35 pm
Contact:

Post by Dwedit » Sat Nov 20, 2010 6:55 pm

I think the original GB Bios (256 bytes) only takes over 0000-00FF. Still needs to see the cartridge ROM for verifying the header and loading the Nintendo logo.
Here come the fortune cookies! Here come the fortune cookies! They're wearing paper hats!

mudlord
Posts: 14
Joined: Sat Jun 12, 2010 8:05 pm
Contact:

Post by mudlord » Sat Nov 20, 2010 7:00 pm

Hehe, so I am a idiot after all. Completely forgot that, so my GB BIOS loading is much more simplified than the GBC one.

Thanks. :oops:

Post Reply