From d029f2a7b6544933fcd35befceae456da29cf280 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9o=20Lam?= <leo@innovatetechnologi.es>
Date: Wed, 28 Feb 2018 17:00:26 +0100
Subject: [PATCH] IPC: Clear X1 when acknowledging a reply

Hardware tests indicate that IOS clears X1 when it acknowledges
an IPC request.
---
 Source/Core/Core/HW/WII_IPC.cpp | 5 +++++
 Source/Core/Core/HW/WII_IPC.h   | 1 +
 Source/Core/Core/IOS/IOS.cpp    | 1 +
 3 files changed, 7 insertions(+)

diff --git a/Source/Core/Core/HW/WII_IPC.cpp b/Source/Core/Core/HW/WII_IPC.cpp
index 5a60b0f04f..d231adcfd2 100644
--- a/Source/Core/Core/HW/WII_IPC.cpp
+++ b/Source/Core/Core/HW/WII_IPC.cpp
@@ -211,6 +211,11 @@ static void UpdateInterrupts(u64 userdata, s64 cyclesLate)
                                    !!(ppc_irq_flags & ppc_irq_masks));
 }
 
+void ClearX1()
+{
+  ctrl.X1 = 0;
+}
+
 void GenerateAck(u32 _Address)
 {
   ctrl.Y2 = 1;
diff --git a/Source/Core/Core/HW/WII_IPC.h b/Source/Core/Core/HW/WII_IPC.h
index d97e7eab0c..34419b8988 100644
--- a/Source/Core/Core/HW/WII_IPC.h
+++ b/Source/Core/Core/HW/WII_IPC.h
@@ -42,6 +42,7 @@ void DoState(PointerWrap& p);
 
 void RegisterMMIO(MMIO::Mapping* mmio, u32 base);
 
+void ClearX1();
 void GenerateAck(u32 _Address);
 void GenerateReply(u32 _Address);
 
diff --git a/Source/Core/Core/IOS/IOS.cpp b/Source/Core/Core/IOS/IOS.cpp
index 90d63c0f4f..cd94693723 100644
--- a/Source/Core/Core/IOS/IOS.cpp
+++ b/Source/Core/Core/IOS/IOS.cpp
@@ -629,6 +629,7 @@ void Kernel::UpdateIPC()
 
   if (m_request_queue.size())
   {
+    ClearX1();
     GenerateAck(m_request_queue.front());
     u32 command = m_request_queue.front();
     m_request_queue.pop_front();