the final piece of f-num/block work

papers/format.md

@@ -29,6 +29,8 @@ furthermore, an `or reserved` indicates this field is always present, but is res
 
 the format versions are:
 
+- 85: Furnace dev85
+- 84: Furnace dev84
 - 83: Furnace dev83
 - 82: Furnace dev82
 - 81: Furnace dev81
@@ -269,7 +271,9 @@ size | description
   1  | ExtCh channel state is shared (>=78) or reserved
   1  | ignore DAC mode change outside of intended channel (>=83) or reserved
   1  | E1xx and E2xx also take priority over Slide00 (>=83) or reserved
- 23  | reserved
+  1  | new Sega PCM (with macros and proper vol/pan) (>=84) or reserved
+  1  | weird f-num/block-based chip pitch slides (>=85) or reserved
+ 21  | reserved
 ```
 
 # instrument

src/engine/engine.h

@@ -43,8 +43,8 @@
 #define BUSY_BEGIN_SOFT softLocked=true; isBusy.lock();
 #define BUSY_END isBusy.unlock(); softLocked=false;
 
-#define DIV_VERSION "dev84"
-#define DIV_ENGINE_VERSION 84
+#define DIV_VERSION "dev85"
+#define DIV_ENGINE_VERSION 85
 
 // for imports
 #define DIV_VERSION_MOD 0xff01

src/engine/fileOps.cpp

@@ -162,6 +162,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
     ds.gbInsAffectsEnvelope=true;
     ds.ignoreDACModeOutsideIntendedChannel=false;
     ds.e1e2AlsoTakePriority=true;
+    ds.fbPortaPause=true;
 
     // 1.1 compat flags
     if (ds.version>24) {
@@ -993,6 +994,9 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     if (ds.version<84) {
       ds.newSegaPCM=false;
     }
+    if (ds.version<85) {
+      ds.fbPortaPause=true;
+    }
     ds.isDMF=false;
 
     reader.readS(); // reserved
@@ -1342,7 +1346,12 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       } else {
         reader.readC();
       }
-      for (int i=0; i<22; i++) {
+      if (ds.version>=85) {
+        ds.fbPortaPause=reader.readC();
+      } else {
+        reader.readC();
+      }
+      for (int i=0; i<21; i++) {
         reader.readC();
       }
     }
@@ -2283,7 +2292,8 @@ SafeWriter* DivEngine::saveFur(bool notPrimary) {
   w->writeC(song.ignoreDACModeOutsideIntendedChannel);
   w->writeC(song.e1e2AlsoTakePriority);
   w->writeC(song.newSegaPCM);
-  for (int i=0; i<22; i++) {
+  w->writeC(song.fbPortaPause);
+  for (int i=0; i<21; i++) {
     w->writeC(0);
   }
 

src/engine/platform/genesisext.cpp

@@ -149,14 +149,22 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
       // what the heck!
       if (!opChan[ch].portaPause) {
         if ((newFreq&0x7ff)>1288) {
+          if (parent->song.fbPortaPause) {
             opChan[ch].portaPauseFreq=(644)|((newFreq+0x800)&0xf800);
             opChan[ch].portaPause=true;
             break;
+          } else {
+            newFreq=(newFreq>>1)|((newFreq+0x800)&0xf800);
+          }
         }
         if ((newFreq&0x7ff)<644) {
+          if (parent->song.fbPortaPause) {
             opChan[ch].portaPauseFreq=newFreq=(1287)|((newFreq-0x800)&0xf800);
             opChan[ch].portaPause=true;
             break;
+          } else {
+            newFreq=(newFreq<<1)|((newFreq-0x800)&0xf800);
+          }
         }
       }
       opChan[ch].portaPause=false;

src/engine/song.h

@@ -324,6 +324,7 @@ struct DivSong {
   bool ignoreDACModeOutsideIntendedChannel;
   bool e1e2AlsoTakePriority;
   bool newSegaPCM;
+  bool fbPortaPause;
 
   DivOrders orders;
   std::vector<DivInstrument*> ins;
@@ -406,7 +407,8 @@ struct DivSong {
     sharedExtStat(true),
     ignoreDACModeOutsideIntendedChannel(false),
     e1e2AlsoTakePriority(false),
-    newSegaPCM(true) {
+    newSegaPCM(true),
+    fbPortaPause(false) {
     for (int i=0; i<32; i++) {
       system[i]=DIV_SYSTEM_NULL;
       systemVol[i]=64;

src/gui/compatFlags.cpp

@@ -101,6 +101,10 @@ void FurnaceGUI::drawCompatFlags() {
     if (ImGui::IsItemHovered()) {
       ImGui::SetTooltip("simulates a bug in where portamento does not work after sliding.");
     }
+    ImGui::Checkbox("FM pitch slide octave boundary odd behavior",&e->song.fbPortaPause);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("if this is on, a pitch slide that crosses the octave boundary will stop for one tick and then continue from the nearest octave boundary.\nfor .dmf compatibility.");
+    }
     ImGui::Checkbox("Apply Game Boy envelope on note-less instrument change",&e->song.gbInsAffectsEnvelope);
     if (ImGui::IsItemHovered()) {
       ImGui::SetTooltip("if this is on, an instrument change will also affect the envelope.");