At the end of July 2011, LM published a free DSP ROM that works with games
using the Zelda UCode. His ROM only has the code to handle UCode loading and a
few utility functions, the rest is missing. This includes the four large sound
mixing functions used by the AX UCode and the DROM containing coefficients used
for polyphase resampling in AX.
This is an improved, updated version of this ROM, which changes the following:
- We now have a free DROM that works for polyphase resampling by "emulating"
linear interpolation. The coefficients contained in the DROM are normally a
list of { c1, c2, c3, c4 } which are used to interpolate a sample value from
four previous samples:
out_sample = prev1 * c1 + prev2 * c2 + prev3 * c3 + prev4 * c4
The coefficients are chosen depending on the fractional part of the current
position (basically, our position between the previous and the next sample).
We can use this fact to generate (c1, c2, c3, c4) for each possible
fractional part so that:
out_sample = prev3 * curr_pos + prev4 * (1 - curr_pos)
Which is the formula for linear interpolation between prev3 and prev4. Linear
interpolation is not as good as polyphase resampling but it still works very
well and I couldn't really hear any difference between the two. If someone
wants to generate real polyphase filter coefficients, they are welcome to
submit a patch.
- The IROM now contains the 4 mixing functions used by the AX UCode: mix_add,
mix_add_two, mix_add_ramp, mix_add_ramp_two. They are large, inlined
functions (probably for performance reasons) in the official DSP IROM, our
version prefers to use a loop. This *should* be more performant with our DSP
JIT implementation, but I did not benchmark that.
Because the new DSP ROM is working just as well as the official ROM in 95% of
cases, it is now shipped by default with Dolphin and will be used with DSPLLE
if you don't have an official DSP ROM in User/GC. It will still display a panic
alert at every boot to notice you that you are using a non official DSP ROM
made by us, which is not perfect.
Games using the CARD, IPL or GBA UCodes are still broken. I don't know what
games this actually impacts, but this is a very small proportion compared to
what works.
# By skidau (30) and Pierre Bourdon (1)
* FIFO-BP: (31 commits)
Set g_bSignalTokenInterrupt on the main thread. Fixes the random hang in Harry Potter: Prisoner of Azkaban.
Used a scheduled event to generate the ARAM DMA interrupt if the DMA is greater than a certain size. Fixes NFS:HP2 GC.
Bumped up the disc transfer speed enough to prevent audio stuttering in Gauntlet: Dark Legacy.
Enabled Synchronise GPU on "SPEED CHALLENGE - Jacques Villeneuve's Racing Vision". Required to go in-game.
Added direct GameCube controller commands to the Serial Interface emulation. Fixes the controls in MaxPlay Classic Games Volume 1 and the Action Replay disc.
Increased the FIFO buffer size to 2MB from 1MB. Fixes Killer 7's Angel boss.
Used an immediate GenerateDSPInterrupt when transferring data from ARAM to MRAM and a scheduled DSP interrupt when transferring data from MRAM to ARAM.
Fixes the audio cutting in and out in the Resident Evil GC games using DSP HLE. Triggered the ARAM interrupt by the scheduler instead of directly in function.
Implemented proper timing for the sample counter in the AudioInterface, removing the previous hack. Cleaned up some of the audio streaming code.
Skipped the EE check if there is a CP interrupt pending.
Disabled "Speed up disc transfer" from the ZTP GC game ini.
Removed the disc seek times for GC games and removed the disc speed option on Wii games. Checked for external exceptions only in mtmsr.
Delayed the interrupts in the EXI Channel.
Merge aram-dma-fixes (r76a13604ef49b522281af75675f044d59a74e871)
Added a patch that bypasses the FIFO reset code in Wallace and Gromit: Project Zoo, allowing it to go in-game.
Made vertex loading take constant time.
Increased the cycle time of the vertex command. Fixes "Speed Challenge: Jacques Villeneuve's Racing Vision".
Moved the setting of the Finish interrupt signal back to the main thread as it was causing Wii games like Resident Evil 4 (Wii) to hang.
Profile stores, fp stores and ps stores only to the fifo write addresses list. This should make the JIT a little faster as it will not be checking for external exceptions unnecessarily.
...
Conflicts:
Source/Core/VideoCommon/Src/PixelEngine.cpp
