Run SMP and DSP in less of a lockstep arrangement

Frameworks/GME/gme/higan/dsp/dsp.cpp

@@ -3,18 +3,25 @@
 
 namespace SuperFamicom {
 
-void DSP::step(unsigned clocks) {
+void DSP::step(uint64_t clocks) {
   clock += clocks;
 }
 
 void DSP::enter() {
-  spc_dsp.run(1);
+  int64_t dsp_clocks = (-clock) / (24 * 4096) + 1;
-  step(24 * 4096);
+  spc_dsp.run(dsp_clocks);
+  step(dsp_clocks * 24 * 4096);
 
   signed count = spc_dsp.sample_count();
-  if(count > 0) {
+  if(count > removed_samples) {
-    for(unsigned n = 0; n < count; n += 2) smp.sample(samplebuffer[n + 0], samplebuffer[n + 1]);
+    for(unsigned n = removed_samples; n < count; n += 2) {
+      if (!smp.sample(samplebuffer[n + 0], samplebuffer[n + 1])) {
+        removed_samples = n;
+        return;
+      }
+    }
     spc_dsp.set_output(samplebuffer, 8192);
+    removed_samples = 0;
   }
 }
 
@@ -34,11 +41,13 @@ void DSP::power() {
   spc_dsp.init(smp.apuram);
   spc_dsp.reset();
   spc_dsp.set_output(samplebuffer, 8192);
+  removed_samples = 0;
 }
 
 void DSP::reset() {
   spc_dsp.soft_reset();
   spc_dsp.set_output(samplebuffer, 8192);
+  removed_samples = 0;
 }
 
 void DSP::channel_enable(unsigned channel, bool enable) {
@@ -55,7 +64,7 @@ void DSP::disable_surround(bool disable) {
 }
 
 DSP::DSP(struct SMP & p_smp)
-    : smp( p_smp ), clock( 0 ) {
+    : smp( p_smp ), clock( 0 ), removed_samples( 0 ) {
   for(unsigned i = 0; i < 8; i++) channel_enabled[i] = true;
 }
 

Frameworks/GME/gme/higan/dsp/dsp.hpp

@@ -9,8 +9,9 @@ namespace SuperFamicom {
 
 struct DSP {
   int64_t clock;
+  unsigned long removed_samples;
 
-  inline void step(unsigned clocks);
+  inline void step(uint64_t clocks);
 
   bool mute();
   uint8_t read(uint8_t addr);

Frameworks/GME/gme/higan/smp/memory.cpp

@@ -22,6 +22,14 @@ void SMP::port_write(uint8_t port, uint8_t data) {
 uint8_t SMP::op_busread(uint16_t addr) {
   unsigned result;
 
+  if ( !(dsp.read( SPC_DSP::r_flg ) & 0x20) ) {
+    int start = 0x100 * dsp.read( SPC_DSP::r_esa );
+    int end  = start + 0x800 * (dsp.read( SPC_DSP::r_edl ) & 0x0F);
+    if ( end > 0x10000 )
+      end = 0x10000;
+    if ( addr >= start || addr < end) synchronize_dsp();
+  }
+    
   switch(addr) {
   case 0xf0:  //TEST -- write-only register
     return 0x00;
@@ -34,6 +42,7 @@ uint8_t SMP::op_busread(uint16_t addr) {
 
   case 0xf3:  //DSPDATA
     //0x80-0xff are read-only mirrors of 0x00-0x7f
+    synchronize_dsp();
     return dsp.read(status.dsp_addr & 0x7f);
 
   case 0xf4:  //CPUIO0
@@ -77,6 +86,7 @@ uint8_t SMP::op_busread(uint16_t addr) {
 }
 
 void SMP::op_buswrite(uint16_t addr, uint8_t data) {
+  synchronize_dsp();
   switch(addr) {
   case 0xf0:  //TEST
     if(regs.p.p) break;  //writes only valid when P flag is clear

Frameworks/GME/gme/higan/smp/smp.cpp

@@ -14,21 +14,26 @@ void SMP::step(unsigned clocks) {
 }
 
 void SMP::synchronize_dsp() {
-  while(dsp.clock < 0 && sample_buffer < sample_buffer_end) dsp.enter();
+  while(dsp.clock < 0) dsp.enter();
 }
 
 void SMP::enter() {
-  while(status.clock_speed != 2 && sample_buffer < sample_buffer_end) op_step();
+  while(sample_buffer < sample_buffer_end) {
-  if (status.clock_speed == 2) {
+    clock -= (sample_buffer_end - sample_buffer) * 24 * 16;
+    while(status.clock_speed != 2 && clock < 0) op_step();
+    if(status.clock_speed == 2) step(-clock);
     synchronize_dsp();
-    if (sample_buffer < sample_buffer_end) {
-      dsp.clock -= 24 * 32 * (sample_buffer_end - sample_buffer) / 2;
-      synchronize_dsp();
-    }
   }
 }
 
 void SMP::render(int16_t * buffer, unsigned count) {
+  while (count > 4096) {
+    sample_buffer = buffer;
+    sample_buffer_end = buffer + 4096;
+    buffer += 4096;
+    count -= 4096;
+    enter();
+  }
   sample_buffer = buffer;
   sample_buffer_end = buffer + count;
   enter();
@@ -46,14 +51,16 @@ void SMP::skip(unsigned count) {
   enter();
 }
 
-void SMP::sample(int16_t left, int16_t right) {
+bool SMP::sample(int16_t left, int16_t right) {
+  if ( sample_buffer_end - sample_buffer < 2 ) return false;
   if ( sample_buffer > ((const int16_t *)0) + 4096 ) {
-    if ( sample_buffer < sample_buffer_end ) *sample_buffer++ = left;
+    *sample_buffer++ = left;
-    if ( sample_buffer < sample_buffer_end ) *sample_buffer++ = right;
+    *sample_buffer++ = right;
   }
-  else if ( sample_buffer < sample_buffer_end ){
+  else {
     sample_buffer += 2;
   }
+  return true;
 }
 
 void SMP::power() {

Frameworks/GME/gme/higan/smp/smp.hpp

@@ -47,7 +47,7 @@ private:
   int16_t * sample_buffer;
   int16_t const* sample_buffer_end;
 public:
-  void sample( int16_t, int16_t );
+  bool sample( int16_t, int16_t );
     
   SMP();
   ~SMP();

Frameworks/GME/gme/higan/smp/timing.cpp

@@ -2,7 +2,7 @@
 
 void SMP::add_clocks(unsigned clocks) {
   step(clocks);
-  synchronize_dsp();
+  //synchronize_dsp();
 }
 
 void SMP::cycle_edge() {