4 files changed, 24 insertions, 12 deletions
diff --git a/common_syms/main.txt b/common_syms/main.txt
index af834cad8..b1f274b58 100644
--- a/common_syms/main.txt
+++ b/common_syms/main.txt
@@ -4,9 +4,9 @@ gMain
 gKeyRepeatContinueDelay
 gSoftResetDisabled
 gIntrTable
-gUnknown_3003578
+sVcountAfterSound
 gLinkVSyncDisabled
 IntrMain_Buffer
-gUnknown_3003D80
-gUnknown_3003D84
+sVcountAtIntr
+sVcountBeforeSound
 gPcmDmaCounter
diff --git a/include/battle_controllers.h b/include/battle_controllers.h
index 0cbda02c0..7dacb1343 100644
--- a/include/battle_controllers.h
+++ b/include/battle_controllers.h
@@ -185,7 +185,7 @@ extern struct UnusedControllerStruct gUnknown_2022870;
 void HandleLinkBattleSetup(void);
 void SetUpBattleVars(void);
 void InitBtlControllers(void);
-void sub_800DD28(void);
+void TryReceiveLinkBattleData(void);
 void PrepareBufferDataTransferLink(u8 bufferId, u16 size, u8 *data);
 
 // emitters
diff --git a/src/battle_controllers.c b/src/battle_controllers.c
index 80b415824..9b8ed77e8 100644
--- a/src/battle_controllers.c
+++ b/src/battle_controllers.c
@@ -481,7 +481,7 @@ static void Task_HandleSendLinkBuffersData(u8 taskId)
     }
 }
 
-void sub_800DD28(void)
+void TryReceiveLinkBattleData(void)
 {
     u8 i;
     s32 j;
diff --git a/src/main.c b/src/main.c
index 1573a2c5b..2f039c23b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -67,9 +67,15 @@ IntrFunc gIntrTable[INTR_COUNT];
 bool8 gLinkVSyncDisabled;
 u32 IntrMain_Buffer[0x200];
 u8 gPcmDmaCounter;
-u8 gUnknown_3003578;
-u8 gUnknown_3003D80;
-u8 gUnknown_3003D84;
+
+// These variables are not defined in RS or Emerald, and are never read.
+// They were likely used to debug the audio engine and VCount interrupt.
+// Define NDEBUG in include/config.h to remove these variables.
+#ifndef NDEBUG
+u8 sVcountAfterSound;
+u8 sVcountAtIntr;
+u8 sVcountBeforeSound;
+#endif
 
 static IntrFunc * const sTimerIntrFunc = gIntrTable + 0x7;
 
@@ -369,11 +375,15 @@ static void VBlankIntr(void)
 
     gPcmDmaCounter = gSoundInfo.pcmDmaCounter;
 
-    gUnknown_3003D84 = REG_VCOUNT;
+#ifndef NDEBUG
+    sVcountBeforeSound = REG_VCOUNT;
+#endif
     m4aSoundMain();
-    gUnknown_3003578 = REG_VCOUNT;
+#ifndef NDEBUG
+    sVcountAfterSound = REG_VCOUNT;
+#endif
 
-    sub_800DD28();
+    TryReceiveLinkBattleData();
     Random();
     UpdateWirelessStatusIndicatorSprite();
 
@@ -398,7 +408,9 @@ static void HBlankIntr(void)
 
 static void VCountIntr(void)
 {
-    gUnknown_3003D80 = REG_VCOUNT;
+#ifndef NDEBUG
+    sVcountAtIntr = REG_VCOUNT;
+#endif
     m4aSoundVSync();
     INTR_CHECK |= INTR_FLAG_VCOUNT;
     gMain.intrCheck |= INTR_FLAG_VCOUNT;