ESFM: add "fast" mode

alters ESFMu to add a fast feedback calculation path

extern/ESFMu/README.md

@@ -1,3 +1,7 @@
+# MODIFIED
+
+this is a modified version of ESFMu which adds a "fast" mode that uses OPL3 feedback calculation rather than patent workaround calculation (which is slow but accurate).
+
 # ESFMu
 
 An emulator for the ESS "ESFM" enhanced OPL3 clone, based on Nuke.YKT's **Nuked OPL3** and reverse-engineering efforts from the community.

extern/ESFMu/esfm.c

@@ -1776,6 +1776,14 @@ ESFM_process_feedback(esfm_chip *chip)
 			phase_acc = (uint32_t)(slot->in.phase_acc - phase_offset * 28);
 			eg_output = slot->in.eg_output;
 
+			if (chip->fast_mode) {
+				phase_feedback = (slot->in.fb_out0 + slot->in.fb_out1) >> 2;
+				slot->in.fb_out1 = slot->in.fb_out0;
+				phase = phase_feedback >> mod_in_shift;
+				phase += phase_acc >> 9;
+				wave_out = slot->in.fb_out0 = ESFM_envelope_wavegen(waveform, phase, eg_output);
+				phase_acc += phase_offset;
+			} else {
 			// ASM optimizaions!
 #if defined(__GNUC__) && defined(__x86_64__)
 			asm (
@@ -1974,6 +1982,7 @@ ESFM_process_feedback(esfm_chip *chip)
 				phase_acc += phase_offset;
 			}
 #endif
+			}
 
 			// TODO: Figure out - is this how the ESFM chip does it, like the
 			// patent literally says? (it's really hacky...)

extern/ESFMu/esfm.h

@@ -58,7 +58,7 @@ typedef struct _esfm_channel esfm_channel;
 typedef struct _esfm_chip esfm_chip;
 
 
-void ESFM_init (esfm_chip *chip);
+void ESFM_init (esfm_chip *chip, uint8_t fast);
 void ESFM_write_reg (esfm_chip *chip, uint16_t address, uint8_t data);
 void ESFM_write_reg_buffered (esfm_chip *chip, uint16_t address, uint8_t data);
 void ESFM_write_reg_buffered_fast (esfm_chip *chip, uint16_t address, uint8_t data);
@@ -148,6 +148,8 @@ typedef struct _esfm_slot_internal
 	uint16 eg_delay_counter;
 	uint16 eg_delay_counter_compare;
 
+	uint16 fb_out0;
+	uint16 fb_out1;
 } esfm_slot_internal;
 
 struct _esfm_slot
@@ -270,6 +272,8 @@ struct _esfm_chip
 	size_t write_buf_start;
 	size_t write_buf_end;
 	uint64_t write_buf_timestamp;
+
+        flag fast_mode;
 };
 
 #ifdef __cplusplus

extern/ESFMu/esfm_registers.c

@@ -948,7 +948,7 @@ ESFM_set_mode (esfm_chip *chip, bool native_mode)
 
 /* ------------------------------------------------------------------------- */
 void
-ESFM_init (esfm_chip *chip)
+ESFM_init (esfm_chip *chip, uint8_t fast)
 {
 	esfm_slot *slot;
 	esfm_channel *channel;
@@ -999,5 +999,6 @@ ESFM_init (esfm_chip *chip)
 	}
 
 	chip->lfsr = 1;
+	chip->fast_mode = fast;
 }
 

src/engine/dispatchContainer.cpp

@@ -649,6 +649,11 @@ void DivDispatchContainer::init(DivSystem sys, DivEngine* eng, int chanCount, do
       break;
     case DIV_SYSTEM_ESFM:
       dispatch=new DivPlatformESFM;
+      if (isRender) {
+        ((DivPlatformESFM*)dispatch)->setFast(eng->getConfInt("esfmCoreRender",0));
+      } else {
+        ((DivPlatformESFM*)dispatch)->setFast(eng->getConfInt("esfmCore",0));
+      }
       break;
     case DIV_SYSTEM_POWERNOISE:
       dispatch=new DivPlatformPowerNoise;

src/engine/platform/esfm.cpp

@@ -983,7 +983,7 @@ int DivPlatformESFM::getRegisterPoolSize() {
 void DivPlatformESFM::reset() {
   while (!writes.empty()) writes.pop();
 
-  ESFM_init(&chip);
+  ESFM_init(&chip,isFast?1:0);
   // set chip to native mode
   ESFM_write_reg(&chip, 0x105, 0x80);
   // ensure NTS bit in register 0x408 is reset, for smooth envelope rate scaling
@@ -1053,6 +1053,10 @@ void DivPlatformESFM::setFlags(const DivConfig& flags) {
   rate=chipClock/288.0;
 }
 
+void DivPlatformESFM::setFast(bool fast) {
+  isFast=fast;
+}
+
 int DivPlatformESFM::init(DivEngine* p, int channels, int sugRate, const DivConfig& flags) {
   parent=p;
   dumpWrites=false;

src/engine/platform/esfm.h

@@ -120,6 +120,7 @@ class DivPlatformESFM: public DivDispatch {
     };
   FixedQueue<QueuedWrite,2048> writes;
   esfm_chip chip;
+  bool isFast;
 
   unsigned char regPool[ESFM_REG_POOL_SIZE];
   short oldWrites[ESFM_REG_POOL_SIZE];
@@ -201,6 +202,7 @@ class DivPlatformESFM: public DivDispatch {
     void poke(unsigned int addr, unsigned short val);
     void poke(std::vector<DivRegWrite>& wlist);
     void setFlags(const DivConfig& flags);
+    void setFast(bool fast);
     int init(DivEngine* parent, int channels, int sugRate, const DivConfig& flags);
     void quit();
     ~DivPlatformESFM();

src/gui/about.cpp

@@ -216,7 +216,7 @@ const char* aboutLine[]={
   "adpcm by superctr",
   "Nuked-OPL3/OPLL/OPM/OPN2/PSG by nukeykt",
   "YM3812-LLE, YMF262-LLE and YMF276-LLE by nukeykt",
-  "ESFMu by Kagamiin~",
+  "ESFMu (modified version) by Kagamiin~",
   "ymfm by Aaron Giles",
   "MAME SN76496 by Nicola Salmoria",
   "MAME AY-3-8910 by Couriersud",

src/gui/fmPreview.cpp

@@ -350,7 +350,7 @@ void FurnaceGUI::renderFMPreviewESFM(const DivInstrumentFM& params, const DivIns
   bool mult0=false;
 
   if (pos==0) {
-    ESFM_init((esfm_chip*)fmPreviewESFM);
+    ESFM_init((esfm_chip*)fmPreviewESFM,0);
     // set native mode
     ESFM_WRITE(0x105, 0x80);
 

src/gui/gui.h

@@ -1638,6 +1638,7 @@ class FurnaceGUI {
     int opnCore;
     int opl2Core;
     int opl3Core;
+    int esfmCore;
     int arcadeCoreRender;
     int ym2612CoreRender;
     int snCoreRender;
@@ -1648,6 +1649,7 @@ class FurnaceGUI {
     int opnCoreRender;
     int opl2CoreRender;
     int opl3CoreRender;
+    int esfmCoreRender;
     int pcSpeakerOutMethod;
     String yrw801Path;
     String tg100Path;
@@ -1843,6 +1845,7 @@ class FurnaceGUI {
       opnCore(1),
       opl2Core(0),
       opl3Core(0),
+      esfmCore(0),
       arcadeCoreRender(1),
       ym2612CoreRender(0),
       snCoreRender(0),
@@ -1853,6 +1856,7 @@ class FurnaceGUI {
       opnCoreRender(1),
       opl2CoreRender(0),
       opl3CoreRender(0),
+      esfmCoreRender(0),
       pcSpeakerOutMethod(0),
       yrw801Path(""),
       tg100Path(""),

src/gui/settings.cpp

@@ -169,6 +169,11 @@ const char* opl3Cores[]={
   "YMF262-LLE"
 };
 
+const char* esfmCores[]={
+  "ESFMu",
+  "ESFMu (fast)"
+};
+
 const char* pcspkrOutMethods[]={
   "evdev SND_TONE",
   "KIOCSOUND on /dev/tty1",
@@ -1629,6 +1634,17 @@ void FurnaceGUI::drawSettings() {
           ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
           if (ImGui::Combo("##OPL3CoreRender",&settings.opl3CoreRender,opl3Cores,3)) settingsChanged=true;
 
+          ImGui::TableNextRow();
+          ImGui::TableNextColumn();
+          ImGui::AlignTextToFramePadding();
+          ImGui::Text("ESFM");
+          ImGui::TableNextColumn();
+          ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
+          if (ImGui::Combo("##ESFMCore",&settings.esfmCore,esfmCores,2)) settingsChanged=true;
+          ImGui::TableNextColumn();
+          ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
+          if (ImGui::Combo("##ESFMCoreRender",&settings.esfmCoreRender,esfmCores,2)) settingsChanged=true;
+
           ImGui::EndTable();
         }
         ImGui::Separator();
@@ -4108,6 +4124,7 @@ void FurnaceGUI::readConfig(DivConfig& conf, FurnaceGUISettingGroups groups) {
     settings.opnCore=conf.getInt("opnCore",1);
     settings.opl2Core=conf.getInt("opl2Core",0);
     settings.opl3Core=conf.getInt("opl3Core",0);
+    settings.esfmCore=conf.getInt("esfmCore",0);
     settings.arcadeCoreRender=conf.getInt("arcadeCoreRender",1);
     settings.ym2612CoreRender=conf.getInt("ym2612CoreRender",0);
     settings.snCoreRender=conf.getInt("snCoreRender",0);
@@ -4118,6 +4135,7 @@ void FurnaceGUI::readConfig(DivConfig& conf, FurnaceGUISettingGroups groups) {
     settings.opnCoreRender=conf.getInt("opnCoreRender",1);
     settings.opl2CoreRender=conf.getInt("opl2CoreRender",0);
     settings.opl3CoreRender=conf.getInt("opl3CoreRender",0);
+    settings.esfmCoreRender=conf.getInt("esfmCoreRender",0);
 
     settings.pcSpeakerOutMethod=conf.getInt("pcSpeakerOutMethod",0);
 
@@ -4146,6 +4164,7 @@ void FurnaceGUI::readConfig(DivConfig& conf, FurnaceGUISettingGroups groups) {
   clampSetting(settings.opnCore,0,1);
   clampSetting(settings.opl2Core,0,2);
   clampSetting(settings.opl3Core,0,2);
+  clampSetting(settings.esfmCore,0,1);
   clampSetting(settings.arcadeCoreRender,0,1);
   clampSetting(settings.ym2612CoreRender,0,2);
   clampSetting(settings.snCoreRender,0,1);
@@ -4156,6 +4175,7 @@ void FurnaceGUI::readConfig(DivConfig& conf, FurnaceGUISettingGroups groups) {
   clampSetting(settings.opnCoreRender,0,1);
   clampSetting(settings.opl2CoreRender,0,2);
   clampSetting(settings.opl3CoreRender,0,2);
+  clampSetting(settings.esfmCoreRender,0,1);
   clampSetting(settings.pcSpeakerOutMethod,0,4);
   clampSetting(settings.mainFont,0,6);
   clampSetting(settings.patFont,0,6);
@@ -4579,6 +4599,7 @@ void FurnaceGUI::writeConfig(DivConfig& conf, FurnaceGUISettingGroups groups) {
     conf.set("opnCore",settings.opnCore);
     conf.set("opl2Core",settings.opl2Core);
     conf.set("opl3Core",settings.opl3Core);
+    conf.set("esfmCore",settings.esfmCore);
     conf.set("arcadeCoreRender",settings.arcadeCoreRender);
     conf.set("ym2612CoreRender",settings.ym2612CoreRender);
     conf.set("snCoreRender",settings.snCoreRender);
@@ -4589,6 +4610,7 @@ void FurnaceGUI::writeConfig(DivConfig& conf, FurnaceGUISettingGroups groups) {
     conf.set("opnCoreRender",settings.opnCoreRender);
     conf.set("opl2CoreRender",settings.opl2CoreRender);
     conf.set("opl3CoreRender",settings.opl3CoreRender);
+    conf.set("esfmCoreRender",settings.esfmCoreRender);
 
     conf.set("pcSpeakerOutMethod",settings.pcSpeakerOutMethod);
 
@@ -4629,6 +4651,7 @@ void FurnaceGUI::commitSettings() {
     settings.opnCore!=e->getConfInt("opnCore",1) ||
     settings.opl2Core!=e->getConfInt("opl2Core",0) ||
     settings.opl3Core!=e->getConfInt("opl3Core",0) ||
+    settings.esfmCore!=e->getConfInt("esfmCore",0) ||
     settings.arcadeCoreRender!=e->getConfInt("arcadeCoreRender",0) ||
     settings.ym2612CoreRender!=e->getConfInt("ym2612CoreRender",0) ||
     settings.snCoreRender!=e->getConfInt("snCoreRender",0) ||
@@ -4639,6 +4662,7 @@ void FurnaceGUI::commitSettings() {
     settings.opnCoreRender!=e->getConfInt("opnCoreRender",1) ||
     settings.opl2CoreRender!=e->getConfInt("opl2CoreRender",0) ||
     settings.opl3CoreRender!=e->getConfInt("opl3CoreRender",0) ||
+    settings.esfmCoreRender!=e->getConfInt("esfmCoreRender",0) ||
     settings.audioQuality!=e->getConfInt("audioQuality",0) ||
     settings.audioHiPass!=e->getConfInt("audioHiPass",1)
   );

src/main.cpp

@@ -212,7 +212,7 @@ TAParamResult pVersion(String) {
   printf("- YM3812-LLE by nukeykt (GPLv2)\n");
   printf("- YMF262-LLE by nukeykt (GPLv2)\n");
   printf("- YMF276-LLE by nukeykt (GPLv2)\n");
-  printf("- ESFMu by Kagamiin~ (LGPLv2.1)\n");
+  printf("- ESFMu (modified version) by Kagamiin~ (LGPLv2.1)\n");
   printf("- ymfm by Aaron Giles (BSD 3-clause)\n");
   printf("- adpcm by superctr (public domain)\n");
   printf("- MAME SN76496 emulation core by Nicola Salmoria (BSD 3-clause)\n");