From 02f0921b2da2a2f88841f9a001a4a4675f5e61b1 Mon Sep 17 00:00:00 2001
From: refractionpcsx2 <refraction@gmail.com>
Date: Sat, 22 Nov 2025 07:39:17 +0000
Subject: [PATCH] EE: Force sync on EE timer read

---
 pcsx2/Interpreter.cpp                 |  4 +--
 pcsx2/R5900.h                         |  1 +
 pcsx2/R5900OpcodeImpl.cpp             | 35 +++++++++++++++++++++++++++
 pcsx2/x86/ix86-32/iR5900LoadStore.cpp | 12 +++++++++
 4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/pcsx2/Interpreter.cpp b/pcsx2/Interpreter.cpp
index d1ba1f8679..16f848a6be 100644
--- a/pcsx2/Interpreter.cpp
+++ b/pcsx2/Interpreter.cpp
@@ -24,7 +24,7 @@ static bool intExitExecution = false;
 static fastjmp_buf intJmpBuf;
 static u32 intLastBranchTo;
 
-static void intEventTest();
+void intEventTest();
 
 void intUpdateCPUCycles()
 {
@@ -548,7 +548,7 @@ static void intReset()
 	branch2 = 0;
 }
 
-static void intEventTest()
+void intEventTest()
 {
 	// Perform counters, ints, and IOP updates:
 	_cpuEventTest_Shared();
diff --git a/pcsx2/R5900.h b/pcsx2/R5900.h
index b786b54842..3e8e1143e5 100644
--- a/pcsx2/R5900.h
+++ b/pcsx2/R5900.h
@@ -283,6 +283,7 @@ static fpuRegisters& fpuRegs = _cpuRegistersPack.fpuRegs;
 extern bool eeEventTestIsActive;
 
 void intUpdateCPUCycles();
+void intEventTest();
 void intSetBranch();
 
 // This is a special form of the interpreter's doBranch that is run from various
diff --git a/pcsx2/R5900OpcodeImpl.cpp b/pcsx2/R5900OpcodeImpl.cpp
index 4727dfad81..a8943c5a7b 100644
--- a/pcsx2/R5900OpcodeImpl.cpp
+++ b/pcsx2/R5900OpcodeImpl.cpp
@@ -524,6 +524,13 @@ void LB()
 
 	if (!_Rt_) return;
 	cpuRegs.GPR.r[_Rt_].SD[0] = temp;
+
+	// Force event test on EE counter read to improve read + interrupt syncing. Namely ESPN Games.
+	if ((addr & 0xFFFFE0000) == 0x10000000)
+	{
+		intUpdateCPUCycles();
+		intEventTest();
+	}
 }
 
 void LBU()
@@ -533,6 +540,13 @@ void LBU()
 
 	if (!_Rt_) return;
 	cpuRegs.GPR.r[_Rt_].UD[0] = temp;
+
+	// Force event test on EE counter read to improve read + interrupt syncing. Namely ESPN Games.
+	if ((addr & 0xFFFFE0000) == 0x10000000)
+	{
+		intUpdateCPUCycles();
+		intEventTest();
+	}
 }
 
 void LH()
@@ -546,6 +560,13 @@ void LH()
 
 	if (!_Rt_) return;
 	cpuRegs.GPR.r[_Rt_].SD[0] = temp;
+
+	// Force event test on EE counter read to improve read + interrupt syncing. Namely ESPN Games.
+	if ((addr & 0xFFFFE0000) == 0x10000000)
+	{
+		intUpdateCPUCycles();
+		intEventTest();
+	}
 }
 
 void LHU()
@@ -559,6 +580,13 @@ void LHU()
 
 	if (!_Rt_) return;
 	cpuRegs.GPR.r[_Rt_].UD[0] = temp;
+
+	// Force event test on EE counter read to improve read + interrupt syncing. Namely ESPN Games.
+	if ((addr & 0xFFFFE0000) == 0x10000000)
+	{
+		intUpdateCPUCycles();
+		intEventTest();
+	}
 }
 
 void LW()
@@ -572,6 +600,13 @@ void LW()
 
 	if (!_Rt_) return;
 	cpuRegs.GPR.r[_Rt_].SD[0] = (s32)temp;
+
+	// Force event test on EE counter read to improve read + interrupt syncing. Namely ESPN Games.
+	if ((addr & 0xFFFFE0000) == 0x10000000)
+	{
+		intUpdateCPUCycles();
+		intEventTest();
+	}
 }
 
 void LWU()
diff --git a/pcsx2/x86/ix86-32/iR5900LoadStore.cpp b/pcsx2/x86/ix86-32/iR5900LoadStore.cpp
index 7f433de48d..36e155e0be 100644
--- a/pcsx2/x86/ix86-32/iR5900LoadStore.cpp
+++ b/pcsx2/x86/ix86-32/iR5900LoadStore.cpp
@@ -107,9 +107,15 @@ static void recLoad(u32 bits, bool sign)
 		alloc_cb = []() { return _allocX86reg(X86TYPE_GPR, _Rt_, MODE_WRITE); };
 
 	int x86reg;
+	bool needs_flush = false;
 	if (GPR_IS_CONST1(_Rs_))
 	{
 		const u32 srcadr = g_cpuConstRegs[_Rs_].UL[0] + _Imm_;
+
+		// Force event test on EE counter read to improve read + interrupt syncing. Namely ESPN Games.
+		if (bits <= 32 && (srcadr & 0xFFFFE0000) == 0x10000000)
+			needs_flush = true;
+
 		x86reg = vtlb_DynGenReadNonQuad_Const(bits, sign, false, srcadr, alloc_cb);
 	}
 	else
@@ -127,6 +133,12 @@ static void recLoad(u32 bits, bool sign)
 	pxAssert(!_Rt_ || !GPR_IS_CONST1(_Rt_));
 	if (!_Rt_)
 		_freeX86reg(x86reg);
+
+	if (bits <= 32 && needs_flush)
+	{
+		iFlushCall(FLUSH_INTERPRETER);
+		g_branch = 2;
+	}
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////