Prior to 7854bd71098fe556ddc9839ad08d27fab7ecba33, this was used by the debugger for the OpenGL and D3D9 plugins to control logging (via PRIM_LOG and INFO_LOG/DEBUG_LOG in VideoCommon code; PRIM_LOG was changed in 77215fd27ccb7cdeb82fed24a7a8d4d4ad4c33a4), and also framedumping (removed in 64927a2f81fe64503060c949ead525995fd63a2a and 2d8515c0cf754806dc38222c4461053e12df1194), shader dumping (removed in 2d8515c0cf754806dc38222c4461053e12df1194 and this commit), and texture dumping (removed in 54aeec7a8ff6b6e5d050637b6cce8df6d9a8b633). Apart from shader dumping, all of these features have modern alternatives, and shader source code can be seen in RenderDoc if "Enable API Validation Layers" is checked (which also enables source attachment), so there's no point in keeping this around.
This normalization was added in 02ac5e95c84a1d9a46df1dc4102342fb653e36ee, and changed to use floats in 4bf031c0646e91b35777f1ba4e2b0328063bb666. The conversion to floats means that sometimes there is insufficient precision for the normalization process, which results in values of NaN or infinity. Performing the whole process with doubles prevents that, but games also sometimes set the values to NaN or infinity directly (possibly accidentally due to the values not being initialized due to them not being used in the current configuration?).
The version of Mesa currently in use on FifoCI (20.3.5) has issues with NaN. Although this bug has been fixed (b3f3287eac in 21.2.0), FifoCI is stuck with the older version.
This change may or may not be incorrect, but it should result in the same behavior as already present in Dolphin, while working around the Mesa bug.
CARDUCode, GBAUCode, and INITUCode previously didn't have an implementation of it. In practice it's unlikely that this caused an issue, since these uCodes are only active for a few frames at most, but now that GBAUCode doesn't have global state, we can implement it there. I also implemented it for CARDUCode, although our CARDUCode implementation does not have all states handled yet - this is simply future-proofing so that when the card uCode is properly implemented, the save state version does not need to be bumped. INITUCode does not have any state to save, though.
The accuracy improvements are:
* The request mail must be 0xabba0000 exactly; both the low and high parts are checked
* The address is masked with 0x0fffffff
* Before, the global state meant that after the GBA uCode had been used once, it would accept 0xcdd1 commands immediately. Now, it only accepts them after execution has finished.
These lookup tables total 4 megabytes, and contain data that's entirely redundant to the actual cache state (as part of an optimization, though I'm not sure whether the optimization actually is useful). This change instead recomputes these lookup tables when loading the state (which involves filling the lookup table with a marker (0xff), and then setting the 128 * 8 valid entries (1 kilobyte)).
