From 97ed78109c1a0e8501da4b594d944feeae441f85 Mon Sep 17 00:00:00 2001
From: refractionpcsx2 <refraction@gmail.com>
Date: Sat, 30 Jan 2021 02:42:55 +0000
Subject: [PATCH] SPU: Wait 2T when keying on a voice

Just like Delay cycles used to do, but done better and tested on a PS2 to get the correct timings
---
 pcsx2/SPU2/defs.h      |  2 +-
 pcsx2/SPU2/spu2sys.cpp | 65 ++++++++++++++++++++++++++----------------
 2 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/pcsx2/SPU2/defs.h b/pcsx2/SPU2/defs.h
index 94f06955ad..17ec291f2f 100644
--- a/pcsx2/SPU2/defs.h
+++ b/pcsx2/SPU2/defs.h
@@ -193,7 +193,7 @@ struct V_Voice
 	s32 SCurrent;
 
 	// it takes a few ticks for voices to start on the real SPU2?
-	bool Start();
+	void Start();
 	void Stop();
 };
 
diff --git a/pcsx2/SPU2/spu2sys.cpp b/pcsx2/SPU2/spu2sys.cpp
index 62c9cd13df..9b4ebc9e1f 100644
--- a/pcsx2/SPU2/spu2sys.cpp
+++ b/pcsx2/SPU2/spu2sys.cpp
@@ -336,32 +336,11 @@ void V_Core::UpdateEffectsBufferSize()
 	RevBuffers.APF2_R_SRC = EffectsBufferIndexer(Revb.APF2_R_DST - Revb.APF2_SIZE);
 }
 
-bool V_Voice::Start()
+void V_Voice::Start()
 {
-	if (StartA & 7)
-	{
-		fprintf(stderr, " *** Misaligned StartA %05x!\n", StartA);
-		StartA = (StartA + 0xFFFF8) + 0x8;
-	}
-
-	ADSR.Releasing = false;
-	ADSR.Value = 1;
-	ADSR.Phase = 1;
-	SCurrent = 28;
-	LoopMode = 0;
-	SP = 0;
-	LoopFlags = 0;
-	NextA = StartA | 1;
-	Prev1 = 0;
-	Prev2 = 0;
-	PendingLoopStart = false;
-
-	PV1 = PV2 = 0;
-	PV3 = PV4 = 0;
-	NextCrest = -0x8000;
 	PlayCycle = Cycles;
 	LoopCycle = Cycles - 1; // Get it out of the start range as to not confuse it
-	return true;
+	PendingLoopStart = false;
 }
 
 void V_Voice::Stop()
@@ -374,6 +353,37 @@ uint TickInterval = 768;
 static const int SanityInterval = 4800;
 extern void UpdateDebugDialog();
 
+__forceinline bool StartQueuedVoice(uint coreidx, uint voiceidx)
+{
+	V_Voice& vc(Cores[coreidx].Voices[voiceidx]);
+
+	if ((Cycles - vc.PlayCycle) < 2)
+		return false;
+
+	if (vc.StartA & 7)
+	{
+		fprintf(stderr, " *** Misaligned StartA %05x!\n", vc.StartA);
+		vc.StartA = (vc.StartA + 0xFFFF8) + 0x8;
+	}
+
+	vc.ADSR.Releasing = false;
+	vc.ADSR.Value = 1;
+	vc.ADSR.Phase = 1;
+	vc.SCurrent = 28;
+	vc.LoopMode = 0;
+	vc.SP = 0;
+	vc.LoopFlags = 0;
+	vc.NextA = vc.StartA | 1;
+	vc.Prev1 = 0;
+	vc.Prev2 = 0;
+
+	vc.PV1 = vc.PV2 = 0;
+	vc.PV3 = vc.PV4 = 0;
+	vc.NextCrest = -0x8000;
+
+	return true;
+}
+
 __forceinline void TimeUpdate(u32 cClocks)
 {
 	u32 dClocks = cClocks - lClocks;
@@ -429,6 +439,12 @@ __forceinline void TimeUpdate(u32 cClocks)
 		lClocks += TickInterval;
 		Cycles++;
 
+		// Start Queued Voices, they start after 2T (Tested on real HW)
+		for(int c = 0; c < 2; c++)
+			for (int v = 0; v < 24; v++)
+				if(Cores[c].KeyOn & (1 << v))
+					if(StartQueuedVoice(c, v))
+						Cores[c].KeyOn &= ~(1 << v);
 		// Note: IOP does not use MMX regs, so no need to save them.
 		//SaveMMXRegs();
 		Mix();
@@ -1970,8 +1986,7 @@ void StartVoices(int core, u32 value)
 		if (!((value >> vc) & 1))
 			continue;
 
-		if (Cores[core].Voices[vc].Start())
-			Cores[core].KeyOn &= ~(1 << vc);
+		Cores[core].Voices[vc].Start();
 
 		if (IsDevBuild)
 		{