Add reverse playback support

extern/vgsound_emu-modified/vgsound_emu/src/k053260/k053260.cpp

@@ -49,7 +49,7 @@ void k053260_core::voice_t::tick(u32 cycle)
 			if (m_bitpos < 8)
 			{
 				m_bitpos += 8;
-				m_addr	 = bitfield(m_addr + 1, 0, 21);
+				m_addr = m_reverse ? bitfield(m_addr - 1, 0, 21) : bitfield(m_addr + 1, 0, 21);
 				m_remain--;
 				if (m_remain < 0)  // check end flag
 				{
@@ -69,7 +69,7 @@ void k053260_core::voice_t::tick(u32 cycle)
 			if (m_adpcm)
 			{
 				m_bitpos		-= 4;
-				const u8 nibble = bitfield(m_data, m_bitpos & 4, 4);  // get nibble from ROM
+				const u8 nibble = bitfield(m_data, m_reverse ? (~m_bitpos & 4) : (m_bitpos & 4), 4);  // get nibble from ROM
 				if (nibble)
 				{
 					m_output += m_host.adpcm_lut(nibble);
@@ -169,6 +169,7 @@ void k053260_core::write(u8 address, u8 data)
 		case 0x28:	// keyon/off toggle
 			for (int i = 0; i < 4; i++)
 			{
+				m_voice[i].set_reverse(bitfield(data, 4 + i));
 				if (bitfield(data, i) && (!m_voice[i].enable()))
 				{  // rising edge (keyon)
 					m_voice[i].keyon();
@@ -276,6 +277,7 @@ void k053260_core::voice_t::reset()
 	m_loop	  = 0;
 	m_adpcm	  = 0;
 	m_pitch	  = 0;
+	m_reverse = 0;
 	m_start	  = 0;
 	m_length  = 0;
 	m_volume  = 0;

extern/vgsound_emu-modified/vgsound_emu/src/k053260/k053260.hpp

@@ -59,6 +59,7 @@ class k053260_core : public vgsound_emu_core
 					, m_loop(0)
 					, m_adpcm(0)
 					, m_pitch(0)
+					, m_reverse(0)
 					, m_start(0)
 					, m_length(0)
 					, m_volume(0)
@@ -91,6 +92,11 @@ class k053260_core : public vgsound_emu_core
 
 				inline void set_adpcm(bool adpcm) { m_adpcm = adpcm ? 1 : 0; }
 
+				inline void set_reverse(const bool reverse)
+				{
+					m_reverse = reverse ? 1 : 0;
+				}
+
 				inline void length_inc() { m_length = (m_length + 1) & 0xffff; }
 
 				inline void set_pan(u8 pan) { m_pan = pan & 7; }
@@ -114,10 +120,11 @@ class k053260_core : public vgsound_emu_core
 				u16 m_loop	  : 1;	 // loop flag
 				u16 m_adpcm	  : 1;	 // ADPCM flag
 				u16 m_pitch	  : 12;	 // pitch
+				u8 m_reverse  : 1;   // reverse playback
 				u32 m_start	  = 0;	 // start position
 				u16 m_length  = 0;	 // source length
 				u8 m_volume	  = 0;	 // master volume
-				int m_pan	  = -1;	 // master pan
+				s32 m_pan	  = 4;	 // master pan
 				u16 m_counter = 0;	 // frequency counter
 				u32 m_addr	  = 0;	 // current address
 				s32 m_remain  = 0;	 // remain for end sample

src/engine/platform/k053260.cpp

@@ -133,7 +133,7 @@ void DivPlatformK053260::tick(bool sysTick) {
     }
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       unsigned char keyon=regPool[0x28]|(1<<i);
-      unsigned char keyoff=keyon&~(1<<i);
+      unsigned char keyoff=keyon&~(17<<i);
       unsigned char loopon=regPool[0x2a]|(1<<i);
       unsigned char loopoff=loopon&~(1<<i);
       double off=1.0;
@@ -155,10 +155,19 @@ void DivPlatformK053260::tick(bool sysTick) {
         unsigned int length=0;
         if (chan[i].sample>=0 && chan[i].sample<parent->song.sampleLen) {
           start=sampleOffK053260[chan[i].sample];
-          length=start+s->length8;
+          length=s->length8;
+          if (chan[i].reverse) {
+            start+=length;
+            keyon|=(16<<i);
+          }
         }
         if (chan[i].audPos>0) {
-          start=start+MIN(chan[i].audPos,s->length8);
+          if (chan[i].reverse) {
+            start=start-MIN(chan[i].audPos,s->length8);
+          }
+          else {
+            start=start+MIN(chan[i].audPos,s->length8);
+          }
           length=MAX(1,length-chan[i].audPos);
         }
         start=MIN(start,getSampleMemCapacity());
@@ -314,6 +323,12 @@ int DivPlatformK053260::dispatch(DivCommand c) {
       chan[c.chan].audPos=c.value;
       chan[c.chan].setPos=true;
       break;
+    case DIV_CMD_SAMPLE_DIR: {
+      if (chan[c.chan].reverse!=(bool)(c.value&1)) {
+        chan[c.chan].reverse=c.value&1;
+      }
+      break;
+    }
     case DIV_CMD_GET_VOLMAX:
       return 127;
       break;

src/engine/platform/k053260.h

@@ -29,7 +29,7 @@ class DivPlatformK053260: public DivDispatch, public k053260_intf {
     unsigned int audPos;
     int sample, wave;
     int panning;
-    bool setPos;
+    bool setPos, reverse;
     int macroVolMul;
     Channel():
       SharedChannel<int>(127),
@@ -38,6 +38,7 @@ class DivPlatformK053260: public DivDispatch, public k053260_intf {
       wave(-1),
       panning(4),
       setPos(false),
+      reverse(false),
       macroVolMul(64) {}
   };
   Channel chan[4];

src/engine/sysDef.cpp

@@ -1862,7 +1862,10 @@ void DivEngine::registerSystems() {
     {"CH1", "CH2", "CH3", "CH4"},
     {DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM},
     {DIV_INS_K053260, DIV_INS_K053260, DIV_INS_K053260, DIV_INS_K053260},
-    {DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA}
+    {DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA},
+    {
+      {0xdf, {DIV_CMD_SAMPLE_DIR, "DFxx: Set sample playback direction (0: normal; 1: reverse)"}}
+    }
   );
 
   sysDefs[DIV_SYSTEM_DUMMY]=new DivSysDef(

src/gui/debug.cpp

@@ -1101,6 +1101,7 @@ void putDispatchChan(void* data, int chanNum, int type) {
       ImGui::Text("- macroVolMul: %.2x",ch->macroVolMul);
       COMMON_CHAN_DEBUG_BOOL;
       ImGui::TextColored(ch->setPos?colorOn:colorOff,">> SetPos");
+      ImGui::TextColored(ch->reverse?colorOn:colorOff,">> Reverse");
       break;
     }
     default: