Closed max-m closed 6 years ago
The DMG mode register initial values appear to be dependent on the ROM's header, so I'll need to research a bit more into it. What ROMs were used to test this?
Checked my disassembly of the CGB boot ROM. Before booting a DMG game, B is set to the checksum of the title, but ONLY IF it's a Nintendo title with a built in palette. This means the game you were testing is Dr. Mario. :)
f1006d6cf77469092f3b9f266d0a65da9c91ac42 Dr. Mario (World).gb
// Edit: Sniped :)
Also, I'm unsure what happens in the AGB-CGB boot ROM, as it hasn't been dumped and it has B set to a different value after booting.
Hi, in #gbdev at EFnet we discovered that SameBoy’s boot ROM ends with different register values than the official one does. It checks out for the DMG boot ROM, but the CGB ROM differs in both modes of operation. This has thrown bgb’s CGB mode detection off but is fixed now :sweat_smile:
The following values have been optained in
bgb
using the official Nintendo boot ROMs and freshly built ROMs from the current master.