From 43468653a07bc26de73752cffcb4b3576813e576 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Tue, 10 Oct 2023 20:15:58 -0500
Subject: [PATCH] prepare for pre-calculated pitch table

---
 src/asm/spc700/player.s          |  7 +++++++
 src/asm/spc700/snes.s            |  1 +
 src/engine/dispatch.h            | 29 +++++++++++++++++++++++++++++
 src/engine/platform/abstract.cpp |  3 +++
 src/gui/settings.cpp             |  2 +-
 5 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 src/asm/spc700/player.s
 create mode 100644 src/asm/spc700/snes.s

diff --git a/src/asm/spc700/player.s b/src/asm/spc700/player.s
new file mode 100644
index 000000000..6ce6c3673
--- /dev/null
+++ b/src/asm/spc700/player.s
@@ -0,0 +1,7 @@
+; command stream player code for SPC700 architecture.
+
+csTick:
+  ret
+
+csInit:
+  ret
diff --git a/src/asm/spc700/snes.s b/src/asm/spc700/snes.s
new file mode 100644
index 000000000..7127bd4b5
--- /dev/null
+++ b/src/asm/spc700/snes.s
@@ -0,0 +1 @@
+; SNES DivDispatch code.
diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 1a8ec347d..3f2dda6b1 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -267,6 +267,29 @@ struct DivCommand {
     value2(0) {}
 };
 
+struct DivPitchTable {
+  int pitch[(12*128)+1];
+  unsigned char linearity, blockBits;
+  bool period;
+
+  // get pitch
+  int get(int base, int pitch, int pitch2);
+
+  // linear: note
+  // non-linear: get(note,0,0)
+  int getBase(int note);
+
+  // calculate pitch table
+  void init(float tuning, double clock, double divider, int octave, unsigned char linear, bool isPeriod, unsigned char block=0);
+
+  DivPitchTable():
+    linearity(2),
+    blockBits(0),
+    period(false) {
+    memset(pitch,0,sizeof(pitch));
+  }
+};
+
 struct DivDelayedCommand {
   int ticks;
   DivCommand cmd;
@@ -692,6 +715,11 @@ class DivDispatch {
      */
     virtual void renderSamples(int sysID);
 
+    /**
+     * tell this DivDispatch that the tuning and/or pitch linearity has changed, and therefore the pitch table must be regenerated.
+     */
+    virtual void notifyPitchTable();
+
     /**
      * initialize this DivDispatch.
      * @param parent the parent DivEngine.
@@ -718,6 +746,7 @@ class DivDispatch {
     if (chipClock<getClockRangeMin()) chipClock=getClockRangeMin(); \
   }
 
+// NOTE: these definitions may be deprecated in the future. see DivPitchTable.
 // pitch calculation:
 // - a DivDispatch usually contains four variables per channel:
 //   - baseFreq: this changes on new notes, legato, arpeggio and slides.
diff --git a/src/engine/platform/abstract.cpp b/src/engine/platform/abstract.cpp
index 26221ebfd..e0b0229cb 100644
--- a/src/engine/platform/abstract.cpp
+++ b/src/engine/platform/abstract.cpp
@@ -199,6 +199,9 @@ void DivDispatch::renderSamples(int sysID) {
   
 }
 
+void DivDispatch::notifyPitchTable() {
+}
+
 int DivDispatch::init(DivEngine* p, int channels, int sugRate, const DivConfig& flags) {
   return 0;
 }
diff --git a/src/gui/settings.cpp b/src/gui/settings.cpp
index 549f35d23..0195c109c 100644
--- a/src/gui/settings.cpp
+++ b/src/gui/settings.cpp
@@ -3364,7 +3364,7 @@ void FurnaceGUI::drawSettings() {
         // ok, so you decided to read the code.
         // these are the cheat codes:
         // "Debug" - toggles mobile UI
-        // "Nice Amiga cover of the song!" - enables hidden systems (YMU759/SoundUnit/Dummy)
+        // "Nice Amiga cover of the song!" - enables hidden systems (YMU759/Dummy)
         // "42 63" - enables all instrument types
         // "4-bit FDS" - enables partial pitch linearity option
         // "Power of the Chip" - enables options for multi-threaded audio