bsnes/higan/ms/psg/psg.cpp

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#include <ms/ms.hpp>
namespace MasterSystem {
PSG psg;
#include "io.cpp"
#include "tone.cpp"
#include "noise.cpp"
Update to v102r10 release. byuu says: Changelog: - removed Emulator::Interface::Capabilities¹ - MS: improved the PSG emulation a bit - MS: added cheat code support - MS: added save state support² - MD: emulated the PSG³ ¹: there's really no point to it anymore. I intend to add cheat codes to the GBA core, as well as both cheat codes and save states to the Mega Drive core. I no longer intend to emulate any new systems, so these values will always be true. Further, the GUI doesn't respond to these values to disable those features anymore ever since the hiro rewrite, so they're double useless. ²: right now, the Z80 core is using a pointer for HL-\>(IX,IY) overrides. But I can't reliably serialize pointers, so I need to convert the Z80 core to use an integer here. The save states still appear to work fine, but there's the potential for an instruction to execute incorrectly if you're incredibly unlucky, so this needs to be fixed as soon as possible. Further, I still need a way to serialize array<T, Size> objects, and I should also add nall::Boolean serialization support. ³: I don't have a system in place to share identical sound chips. But this chip is so incredibly simple that it's not really much trouble to duplicate it. Further, I can strip out the stereo sound support code from the Game Gear portion, so it's even tinier. Note that the Mega Drive only just barely uses the PSG. Not at all in Altered Beast, and only for a tiny part of the BGM music on Sonic 1, plus his jump sound effect.
2017-02-22 21:25:01 +00:00
#include "serialization.cpp"
auto PSG::Enter() -> void {
while(true) scheduler.synchronize(), psg.main();
}
auto PSG::main() -> void {
tone0.run();
tone1.run();
tone2.run();
noise.run();
int left = 0;
Update to v102r15 release. byuu says: Changelog: - nall: added DSP::IIR::OnePole (which is a first-order IIR filter) - FC/APU: removed strong highpass, weak hipass filters (and the dummied out lowpass filter) - MS,GG,MD/PSG: removed lowpass filter - MS,GG,MD/PSG: audio was not being centered properly; removed centering for now - MD/YM2612: fixed clipping of accumulator from 18 signed bits to 14 signed bits (-0x2000 to +0x1fff) [Cydrak] - MD/YM2612: removed lowpass filter - PCE/PSG: audio was not being centered properly; removed centering for now First thing is that I've removed all of the ad-hoc audio filtering. Emulator::Stream intrinsically provides a three-pass, second-order biquad IIR butterworth lowpass filter that clips frequencies above 20KHz with very good attenuation (as good as IIR gets, anyway.) It doesn't really make sense to have the various cores running additional lowpass filters. If we want to filter frequencies below 20KHz, then I can adapt Emulator::Audio::createStream() to take a cutoff frequency value, and we can do it all at once, with much better quality. Right now, I don't know what frequencies are best to cut off the various other audio cores, so they're just gone for now. As for the highpass filters for the Famicom core, well ... you don't get aliasing from resampling low frequencies. And generally speaking, too low a frequency will be inaudible anyway. All these were doing was killing possible bass (if they were too strong.) We can add them again, but only if someone can convert Ryphecha's ad-hoc magic integers into a frequency cutoff. In which case, I'll use my biquad IIR filter to do it even better. On this note, it may prove useful to do this for the MD PSG as well, to try and head off unnecessary clamping when mixing with the YM2612. Finally, there was the audio centering issue that affected the MS,GG,MD,PCE,SG cores. It was flooring the "silent" audio level, which was resulting in extremely heavy distortion if you tried listening to higan and, say, audacious at the same time. Without the botched centering, this distortion is completely gone now. However, without any centering, we've halved the potential volume range. This means the audio slider in higan's audio settings panel will start clamping twice as quickly. So ultimately, we need to figure out how to fix the centering. This isn't as simple as just subtracting less. We will probably have to center every individual audio channel before summing them to do this properly. Results: On the Mega Drive, Altered Beast sounds quite a bit better, a lot less distortion now. But it's still not perfect, especially sound effects. Further, Bare Knuckle / Streets of Rage still has really bad sound effects. It looks like I broke something in Cydrak's code when trying to adapt it to my style =(
2017-03-06 20:23:22 +00:00
left += levels[tone0.volume] * tone0.output * tone0.left;
left += levels[tone1.volume] * tone1.output * tone1.left;
left += levels[tone2.volume] * tone2.output * tone2.left;
left += levels[noise.volume] * noise.output * noise.left;
int right = 0;
Update to v102r15 release. byuu says: Changelog: - nall: added DSP::IIR::OnePole (which is a first-order IIR filter) - FC/APU: removed strong highpass, weak hipass filters (and the dummied out lowpass filter) - MS,GG,MD/PSG: removed lowpass filter - MS,GG,MD/PSG: audio was not being centered properly; removed centering for now - MD/YM2612: fixed clipping of accumulator from 18 signed bits to 14 signed bits (-0x2000 to +0x1fff) [Cydrak] - MD/YM2612: removed lowpass filter - PCE/PSG: audio was not being centered properly; removed centering for now First thing is that I've removed all of the ad-hoc audio filtering. Emulator::Stream intrinsically provides a three-pass, second-order biquad IIR butterworth lowpass filter that clips frequencies above 20KHz with very good attenuation (as good as IIR gets, anyway.) It doesn't really make sense to have the various cores running additional lowpass filters. If we want to filter frequencies below 20KHz, then I can adapt Emulator::Audio::createStream() to take a cutoff frequency value, and we can do it all at once, with much better quality. Right now, I don't know what frequencies are best to cut off the various other audio cores, so they're just gone for now. As for the highpass filters for the Famicom core, well ... you don't get aliasing from resampling low frequencies. And generally speaking, too low a frequency will be inaudible anyway. All these were doing was killing possible bass (if they were too strong.) We can add them again, but only if someone can convert Ryphecha's ad-hoc magic integers into a frequency cutoff. In which case, I'll use my biquad IIR filter to do it even better. On this note, it may prove useful to do this for the MD PSG as well, to try and head off unnecessary clamping when mixing with the YM2612. Finally, there was the audio centering issue that affected the MS,GG,MD,PCE,SG cores. It was flooring the "silent" audio level, which was resulting in extremely heavy distortion if you tried listening to higan and, say, audacious at the same time. Without the botched centering, this distortion is completely gone now. However, without any centering, we've halved the potential volume range. This means the audio slider in higan's audio settings panel will start clamping twice as quickly. So ultimately, we need to figure out how to fix the centering. This isn't as simple as just subtracting less. We will probably have to center every individual audio channel before summing them to do this properly. Results: On the Mega Drive, Altered Beast sounds quite a bit better, a lot less distortion now. But it's still not perfect, especially sound effects. Further, Bare Knuckle / Streets of Rage still has really bad sound effects. It looks like I broke something in Cydrak's code when trying to adapt it to my style =(
2017-03-06 20:23:22 +00:00
right += levels[tone0.volume] * tone0.output * tone0.right;
right += levels[tone1.volume] * tone1.output * tone1.right;
right += levels[tone2.volume] * tone2.output * tone2.right;
right += levels[noise.volume] * noise.output * noise.right;
Update to v102r15 release. byuu says: Changelog: - nall: added DSP::IIR::OnePole (which is a first-order IIR filter) - FC/APU: removed strong highpass, weak hipass filters (and the dummied out lowpass filter) - MS,GG,MD/PSG: removed lowpass filter - MS,GG,MD/PSG: audio was not being centered properly; removed centering for now - MD/YM2612: fixed clipping of accumulator from 18 signed bits to 14 signed bits (-0x2000 to +0x1fff) [Cydrak] - MD/YM2612: removed lowpass filter - PCE/PSG: audio was not being centered properly; removed centering for now First thing is that I've removed all of the ad-hoc audio filtering. Emulator::Stream intrinsically provides a three-pass, second-order biquad IIR butterworth lowpass filter that clips frequencies above 20KHz with very good attenuation (as good as IIR gets, anyway.) It doesn't really make sense to have the various cores running additional lowpass filters. If we want to filter frequencies below 20KHz, then I can adapt Emulator::Audio::createStream() to take a cutoff frequency value, and we can do it all at once, with much better quality. Right now, I don't know what frequencies are best to cut off the various other audio cores, so they're just gone for now. As for the highpass filters for the Famicom core, well ... you don't get aliasing from resampling low frequencies. And generally speaking, too low a frequency will be inaudible anyway. All these were doing was killing possible bass (if they were too strong.) We can add them again, but only if someone can convert Ryphecha's ad-hoc magic integers into a frequency cutoff. In which case, I'll use my biquad IIR filter to do it even better. On this note, it may prove useful to do this for the MD PSG as well, to try and head off unnecessary clamping when mixing with the YM2612. Finally, there was the audio centering issue that affected the MS,GG,MD,PCE,SG cores. It was flooring the "silent" audio level, which was resulting in extremely heavy distortion if you tried listening to higan and, say, audacious at the same time. Without the botched centering, this distortion is completely gone now. However, without any centering, we've halved the potential volume range. This means the audio slider in higan's audio settings panel will start clamping twice as quickly. So ultimately, we need to figure out how to fix the centering. This isn't as simple as just subtracting less. We will probably have to center every individual audio channel before summing them to do this properly. Results: On the Mega Drive, Altered Beast sounds quite a bit better, a lot less distortion now. But it's still not perfect, especially sound effects. Further, Bare Knuckle / Streets of Rage still has really bad sound effects. It looks like I broke something in Cydrak's code when trying to adapt it to my style =(
2017-03-06 20:23:22 +00:00
stream->sample(sclamp<16>(left) / 32768.0, sclamp<16>(right) / 32768.0);
Update to v102r10 release. byuu says: Changelog: - removed Emulator::Interface::Capabilities¹ - MS: improved the PSG emulation a bit - MS: added cheat code support - MS: added save state support² - MD: emulated the PSG³ ¹: there's really no point to it anymore. I intend to add cheat codes to the GBA core, as well as both cheat codes and save states to the Mega Drive core. I no longer intend to emulate any new systems, so these values will always be true. Further, the GUI doesn't respond to these values to disable those features anymore ever since the hiro rewrite, so they're double useless. ²: right now, the Z80 core is using a pointer for HL-\>(IX,IY) overrides. But I can't reliably serialize pointers, so I need to convert the Z80 core to use an integer here. The save states still appear to work fine, but there's the potential for an instruction to execute incorrectly if you're incredibly unlucky, so this needs to be fixed as soon as possible. Further, I still need a way to serialize array<T, Size> objects, and I should also add nall::Boolean serialization support. ³: I don't have a system in place to share identical sound chips. But this chip is so incredibly simple that it's not really much trouble to duplicate it. Further, I can strip out the stereo sound support code from the Game Gear portion, so it's even tinier. Note that the Mega Drive only just barely uses the PSG. Not at all in Altered Beast, and only for a tiny part of the BGM music on Sonic 1, plus his jump sound effect.
2017-02-22 21:25:01 +00:00
step(1);
}
auto PSG::step(uint clocks) -> void {
Thread::step(clocks);
synchronize(cpu);
}
auto PSG::power() -> void {
//Master System is monaural; Game Gear is stereo
//use stereo mode for both; output same sample to both channels for Master System
create(PSG::Enter, system.colorburst() / 16.0);
stream = Emulator::audio.createStream(2, frequency());
Update to v102r16 release. byuu says: Changelog: - Emulator::Stream now allows adding low-pass and high-pass filters dynamically - also accepts a pass# count; each pass is a second-order biquad butterworth IIR filter - Emulator::Stream no longer automatically filters out >20KHz frequencies for all streams - FC: added 20Hz high-pass filter; 20KHz low-pass filter - GB: removed simple 'magic constant' high-pass filter of unknown cutoff frequency (missed this one in the last WIP) - GB,SGB,GBC: added 20Hz high-pass filter; 20KHz low-pass filter - MS,GG,MD/PSG: added 20Hz high-pass filter; 20KHz low-pass filter - MD: added save state support (but it's completely broken for now; sorry) - MD/YM2612: fixed Voice#3 per-operator pitch support (fixes sound effects in Streets of Rage, etc) - PCE: added 20Hz high-pass filter; 20KHz low-pass filter - WS,WSC: added 20Hz high-pass filter; 20KHz low-pass filter So, the point of the low-pass filters is to remove frequencies above human hearing. If we don't do this, then resampling will introduce aliasing that results in sounds that are audible to the human ear. Which basically an annoying buzzing sound. You'll definitely hear the improvement from these in games like Mega Man 2 on the NES. Of course, these already existed before, so this WIP won't sound better than previous WIPs. The high-pass filters are a little more complicated. Their main role is to remove DC bias and help to center the audio stream. I don't understand how they do this at all, but ... that's what everyone who knows what they're talking about says, thus ... so be it. I have set all of the high-pass filters to 20Hz, which is below the limit of human hearing. Now this is where it gets really interesting ... technically, some of these systems actually cut off a lot of range. For instance, the GBA should technically use an 800Hz high-pass filter when output is done through the system's speakers. But of course, if you plug in headphones, you can hear the lower frequencies. Now 800Hz ... you definitely can hear. At that level, nearly all of the bass is stripped out and the audio is very tinny. Just like the real system. But for now, I don't want to emulate the audio being crushed that badly. I'm sticking with 20Hz everywhere since it won't negatively affect audio quality. In fact, you should not be able to hear any difference between this WIP and the previous WIP. But theoretically, DC bias should mostly be removed as a result of these new filters. It may be that we need to raise the values on some cores in the future, but I don't want to do that until we know for certain that we have to. What I can say is that compared to even older WIPs than r15 ... the removal of the simple one-pole low-pass and high-pass filters with the newer three-pass, second-order filters should result in much better attenuation (less distortion of audible frequencies.) Probably not enough to be noticeable in a blind test, though.
2017-03-08 20:20:40 +00:00
stream->addLowPassFilter(20000.0, 3);
stream->addHighPassFilter(20.0, 3);
select = 0;
for(auto n : range(15)) {
Update to v102r11 release. byuu says: Changelog: - MD: connected 32KB cartridge RAM up to every Genesis game under 2MB loaded¹ - MS, GG, MD: improved PSG noise channel emulation, hopefully² - MS, GG, MD: lowered PSG volume so that the lowpass doesn't clamp samples³ - MD: added read/write handlers for VRAM, VSRAM, CRAM - MD: block VRAM copy when CD4 is clear⁴ - MD: rewrote VRAM fill, VRAM copy to be byte-based⁵ - MD: VRAM fill byte set should fall through to regular data port write handler⁶ ¹: the header parsing for backup RAM is really weird. It's spaces when not used, and seems to be 0x02000001-0x02003fff for the Shining games. I don't understand why it starts at 0x02000001 instead of 0x02000000. So I'm just forcing every game to have 32KB of RAM for now. There's also special handling for ROMs > 2MB that also have RAM (Phantasy Star IV, etc) where there's a toggle to switch between ROM and RAM. For now, that's not emulated. I was hoping the Shining games would run after this, but they're still dead-locking on me :( ²: Cydrak pointed out some flaws in my attempt to implement what he had. I was having trouble understanding what he meant, so I went back and read the docs on the sound chip and tried implementing the counter the way the docs describe. Hopefully I have this right, but I don't know of any good test ROMs to make sure my noise emulation is correct. The docs say the shifted-out value goes to the output instead of the low bit of the LFSR, so I made that change as well. I think I hear the noise I'm supposed to in Sonic Marble Zone now, but it seems like it's not correct in Green Hill Zone, adding a bit of an annoying buzz to the background music. Maybe it sounds better with the YM2612, but more likely, I still screwed something up :/ ³: it's set to 50% range for both cores right now. For the MD, it will need to be 25% once YM2612 emulation is in. ⁴: technically, this deadlocks the VDP until a hard reset. I could emulate this, but for now I just don't do the VRAM copy in this case. ⁵: VSRAM fill and CRAM fill not supported in this new mode. They're technically undocumented, and I don't have good notes on how they work. I've been seeing conflicting notes on whether the VRAM fill buffer is 8-bits or 16-bits (I chose 8-bits), and on whether you write the low byte and then high byte of each words, or the high byte and then low byte (I chose the latter.) The VRAM copy improvements fix the opening text in Langrisser II, so that's great. ⁶: Langrisser II sets the transfer length to one less than needed to fill the background letter tile on the scenario overview screen. After moving to byte-sized transfers, a black pixel was getting stuck there. So effectively, VRAM fill length becomes DMA length + 1, and the first byte uses the data port so it writes a word value instead of just a byte value. Hopefully this is all correct, although it probably gets way more complicated with the VDP FIFO.
2017-02-25 11:11:46 +00:00
levels[n] = 0x2000 * pow(2, n * -2.0 / 6.0) + 0.5;
}
levels[15] = 0;
tone0.power();
tone1.power();
tone2.power();
noise.power();
}
}