bsnes/higan/md/psg/psg.hpp

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Update to v102r14 release. byuu says: Changelog: - (MS,GG,MD)/PSG: flip output bit from noise channel [TmEE] - MD/YM2612: rewrite YM2612::Channel functions to YM2612::Channel::Operator functions¹ - MD/YM2612: pitch/octave I/O registers should set reload, not value (fixes sound in most games) - MD/YM2612: don't try to sign-extend raw PCM values (fixes Shining Force opening music) - MD/YM2612: various algorithm simplifications; conversions from `*`, `/`, `%` to `<<`, `>>`; etc. Overall ... Sonic the Hedgehog sounds really, really great. Almost perfect, but there's a bit of clamping going on in the special zones. Langrisser II sounds really great. Shining Force sounds pretty much perfect. Bare Knucles (Streets of Rage) does pretty badly ... punches sound more like dinging a salad fork on a wine glass, heh. Altered Beast is extremely broken ... no music at the title screen, very distorted in-game music. I suspect a bug outside of the YM2612 is affecting this game. So, the YM2612 emulation isn't perfect, but it's a really good start to the most complex sound chip in all of higan. Hopefully the VRC7 and YM2413 will prove to be less ferocious ... not that I'm in any rush to work on either. The former is going to need the NES mapper rewrite to be done first, and the latter is cool but not very necessary since all those games have fallbacks to the inferior PSG audio. But really ... I can't thank Cydrak enough for doing this for me. It would have probably taken me months to parse through all of the documentation on this chip (most of which is in a 55-page thread on spritesmind that is filled with wrong/outdated information at the start, and corrections as you go deeper.) Not to mention, learning about what the hell detuning, low-frequency oscillation, tremolo, vibrato, etc were all about. Or how those algorithms to compute the final output work. Or the dozens of special cases littered in there to make everything sound good. Fierce, nasty chip that. Now the last real problem is save states ... the Mega Drive is going to be the trickiest of all to implement with libco. There are lots of areas where one chip will deadlock another chip while it completes some operation. We don't have a choice but to force those stalls to abort anyway, in order to let libco reach the start of its entry point once again. I don't know what kind of impact that'll have on states ... I suspect they'll work almost as reliably as the SNES does, but I can't know that until I implement it. It's going to be pretty nasty, though. ¹: this basically removes a lot of unnecessary op. prefixes and the need to capture `auto& op = operators[index]` at the start of every function. I wanted to have subfunctions like `YM2612::Channel::Operator::Envelope::run()`, etc but unfortunately, pretty much all of the envelope, phase, pitch, level functions need to access each other's state.
2017-03-03 10:45:07 +00:00
//TI SN76489 (derivative)
struct PSG : Thread {
Update to v101r12 release. byuu says: Changelog: - new md/bus/ module for bus reads/writes - abstracts byte/word accesses wherever possible (everything but RAM; forces all but I/O to word, I/O to byte) - holds the system RAM since that's technically not part of the CPU anyway - added md/controller and md/system/peripherals - added emulation of gamepads - added stub PSG audio output (silent) to cap the framerate at 60fps with audio sync enabled - fixed VSRAM reads for plane vertical scrolling (two bugs here: add instead of sub; interlave plane A/B) - mask nametable read offsets (can't exceed 8192-byte nametables apparently) - emulated VRAM/VSRAM/CRAM reads from VDP data port - fixed sprite width/height size calculations - added partial emulation of 40-tile per scanline limitation (enough to fix Sonic's title screen) - fixed off-by-one sprite range testing - fixed sprite tile indexing - Vblank happens at Y=224 with overscan disabled - unsure what happens when you toggle it between Y=224 and Y=240 ... probably bad things - fixed reading of address register for ADDA, CMPA, SUBA - fixed sign extension for MOVEA effect address reads - updated MOVEM to increment the read addresses (but not writeback) for (aN) mode With all of that out of the way, we finally have Sonic the Hedgehog (fully?) playable. I played to stage 1-2 and through the special stage, at least. EDIT: yeah, we probably need HIRQs for Labyrinth Zone. Not much else works, of course. Most games hang waiting on the Z80, and those that don't (like Altered Beast) are still royally screwed. Tons of features still missing; including all of the Z80/PSG/YM2612. A note on the perihperals this time around: the Mega Drive EXT port is basically identical to the regular controller ports. So unlike with the Famicom and Super Famicom, I'm inheriting the exension port from the controller class.
2016-08-21 22:11:24 +00:00
shared_pointer<Emulator::Stream> stream;
static auto Enter() -> void;
auto main() -> void;
auto step(uint clocks) -> void;
Update to v105r1 release. byuu says: Changelog: - higan: readded support for soft-reset to Famicom, Super Famicom, Mega Drive cores (work in progress) - handhelds lack soft reset obviously - the PC Engine also lacks a physical reset button - the Master System's reset button acts like a gamepad button, so can't show up in the menu - Mega Drive: power cycle wasn't initializing CPU (M68K) or APU (Z80) RAM - Super Famicom: fix SPC700 opcode 0x3b regression; fixes Majuu Ou [Jonas Quinn] - Super Famicom: fix SharpRTC save regression; fixes Dai Kaijuu Monogatari II's real-time clock [Talarubi] - Super Famicom: fix EpsonRTC save regression; fixes Tengai Makyou Zero's real-time clock [Talarubi] - Super Famicom: removed `*::init()` functions, as they were never used - Super Famicom: removed all but two `*::load()` functions, as they were not used - higan: added option to auto-save backup RAM every five seconds (enabled by default) - this is in case the emulator crashes, or there's a power outage; turn it off under advanced settings if you want - libco: updated license from public domain to ISC, for consistency with nall, ruby, hiro - nall: Linux compiler defaults to g++; override with g++-version if g++ is <= 4.8 - FreeBSD compiler default is going to remain g++49 until my dev box OS ships with g++ >= 4.9 Errata: I have weird RAM initialization constants, thanks to hex_usr and onethirdxcubed for both finding this: http://wiki.nesdev.com/w/index.php?title=CPU_power_up_state&diff=11711&oldid=11184 I'll remove this in the next WIP.
2017-11-06 22:05:54 +00:00
auto power(bool reset) -> void;
Update to v102r08 release. byuu says: Changelog: - PCE: restructured VCE, VDCs to run one scanline at a time - PCE: bound VDCs to 1365x262 timing (in order to decouple the VDCs from the VCE) - PCE: the two changes above allow save states to function; also grants a minor speed boost - PCE: added cheat code support (uses 21-bit bus addressing; compare byte will be useful here) - 68K: fixed `mov *,ccr` to read two bytes instead of one [Cydrak] - Z80: emulated /BUSREQ, /BUSACK; allows 68K to suspend the Z80 [Cydrak] - MD: emulated the Z80 executing instructions [Cydrak] - MD: emulated Z80 interrupts (triggered during each Vblank period) [Cydrak] - MD: emulated Z80 memory map [Cydrak] - MD: added stubs for PSG, YM2612 accesses [Cydrak] - MD: improved bus emulation [Cydrak] The PCE core is pretty much ready to go. The only major feature missing is FM modulation. The Mega Drive improvements let us start to see the splash screens for Langrisser II, Shining Force, Shining in the Darkness. I was hoping I could get them in-game, but no such luck. My Z80 implementation is probably flawed in some way ... now that I think about it, I believe I missed the BusAPU::reset() check for having been granted access to the Z80 first. But I doubt that's the problem. Next step is to implement Cydrak's PSG core into the Master System emulator. Once that's in, I'm going to add save states and cheat code support to the Master System core. Next, I'll add the PSG core into the Mega Drive. Then I'll add the 'easy' PCM part of the YM2612. Then the rest of the beastly YM2612 core. Then finally, cap things off with save state and cheat code support. Should be nearing a new release at that point.
2017-02-20 08:13:10 +00:00
//io.cpp
auto write(uint8 data) -> void;
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
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
//serialization.cpp
auto serialize(serializer&) -> void;
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
private:
struct Tone {
//tone.cpp
auto run() -> void;
auto power() -> void;
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
//serialization.cpp
auto serialize(serializer&) -> void;
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
uint4 volume;
uint10 counter;
uint10 pitch;
uint1 output;
} tone0, tone1, tone2;
struct Noise {
//noise.cpp
auto run() -> void;
auto power() -> void;
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
//serialization.cpp
auto serialize(serializer&) -> void;
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
uint4 volume;
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
uint10 counter;
uint10 pitch;
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
uint1 enable;
uint2 rate;
uint16 lfsr;
uint1 clock;
uint1 output;
} noise;
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
uint3 select;
int16 levels[16];
};
extern PSG psg;