- coef: Explicitly set 23 different values that are used by GBA UCode,
and tweaked overall parameters to more closely match those 23 values.
- irom: Moved a few functions to their proper places, updated BootUCode
to configure DMA transfers using AX registers as well as IX registers
(the GBA UCode uses this to do two sequential transfers in one call),
and added partial functions used by GBA UCode.
All functions were reverse-engineered solely based off of observed
effects on the virtual machine: register states before-and-after, dmem
interactions, and DMA transfers. The specific coefficients were observed
being read from dmem, and must be exactly those values to function
properly. I have no knowledge of how the official ROM implements these
functions, or how it is implemented overall.
Tested with The Legend of Zelda: Four Swords Adventures, Final Fantasy
Crystal Chronicles, and Billy Hatcher and the Giant Egg (to download
ChuChu Rocket!).
`P_REG1C` had the same value as `P_ACCL`, so was causing spurious errors
when used with ACCM registers. Gcdsptool (which calls this `P_ACCLM`)
gives it the value `P_REG | 0x1c10` instead, and handles errors in the
same block as other REG## enums.
This makes the interface slightly cleaner and a bit more consistent
with the other getters. Still not fully the same, since the others
don't really handle failures with std::optional; but at least the
value is returned by value now, as opposed to having the function
take a pointer to a u64.
This gets rid of some assumptions that non-DiscIO code was making about
volume types. It's better to encapsulate as many of the volume type
differences as possible in DiscIO.
Made possible by PR #2353.
This is more reliable, as this guarantees subsystems will be
shut down in the same order they were initialised (if they were
initialised). It also allows us to stop keeping track of what needs to
be shut down manually and just return in case of errors.
This should prevent the emulator from getting totally stuck when
the boot process does fail.
Shawn Hoffman