From b063f15dccf030e9b4fdeac189f779181d25db9c Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Wed, 8 Jun 2022 20:22:20 -0700
Subject: [PATCH 1/6] DSPHLE: Replace CMailHandler::IsEmpty with
 CMailHandler::HasPending

---
 Source/Core/Core/HW/DSPHLE/MailHandler.cpp | 4 ++--
 Source/Core/Core/HW/DSPHLE/MailHandler.h   | 2 +-
 Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp | 4 ++--
 Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp  | 4 ++--
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index ce6b8f8a1a..46019abc6f 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -75,9 +75,9 @@ void CMailHandler::Clear()
     m_Mails.pop();
 }
 
-bool CMailHandler::IsEmpty() const
+bool CMailHandler::HasPending() const
 {
-  return m_Mails.empty();
+  return !m_Mails.empty();
 }
 
 void CMailHandler::Halt(bool _Halt)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index e5afbc9869..773cf042bb 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -23,7 +23,7 @@ public:
   void Clear();
   void Halt(bool _Halt);
   void DoState(PointerWrap& p);
-  bool IsEmpty() const;
+  bool HasPending() const;
 
   u16 ReadDSPMailboxHigh();
   u16 ReadDSPMailboxLow();
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
index bf8da5db10..23ee74bec8 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
@@ -28,8 +28,8 @@ void CARDUCode::Initialize()
 
 void CARDUCode::Update()
 {
-  // check if we have to sent something
-  if (!m_mail_handler.IsEmpty())
+  // check if we have something to send
+  if (m_mail_handler.HasPending())
   {
     DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP);
   }
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
index 6704a489ec..49816fe6fd 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
@@ -85,8 +85,8 @@ void GBAUCode::Initialize()
 
 void GBAUCode::Update()
 {
-  // check if we have to send something
-  if (!m_mail_handler.IsEmpty())
+  // check if we have something to send
+  if (m_mail_handler.HasPending())
   {
     DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP);
   }

From 567f9bede4db4298c709c5234bfa103c2a3fd279 Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Wed, 8 Jun 2022 19:59:27 -0700
Subject: [PATCH 2/6] DSPHLE: Remove unneeded calls to m_mail_handler.Clear()

It's cleared whenever the uCode changes, so there's no reason to clear it in a destructor or during initialization.

I've also renamed it to ClearPending.
---
 Source/Core/Core/HW/DSPHLE/DSPHLE.cpp       | 4 ++--
 Source/Core/Core/HW/DSPHLE/MailHandler.cpp  | 7 +++----
 Source/Core/Core/HW/DSPHLE/MailHandler.h    | 6 +++++-
 Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp    | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp  | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp   | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp   | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp | 1 -
 8 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
index c686930383..9e17a78ecc 100644
--- a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
+++ b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
@@ -67,7 +67,7 @@ void DSPHLE::SendMailToDSP(u32 mail)
 
 void DSPHLE::SetUCode(u32 crc)
 {
-  m_mail_handler.Clear();
+  m_mail_handler.ClearPending();
   m_ucode = UCodeFactory(crc, this, m_wii);
   m_ucode->Initialize();
 }
@@ -77,7 +77,7 @@ void DSPHLE::SetUCode(u32 crc)
 // Even callers are deleted.
 void DSPHLE::SwapUCode(u32 crc)
 {
-  m_mail_handler.Clear();
+  m_mail_handler.ClearPending();
 
   if (m_last_ucode && UCodeInterface::GetCRC(m_last_ucode.get()) == crc)
   {
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index 46019abc6f..b1d0377ec2 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -19,7 +19,6 @@ CMailHandler::CMailHandler()
 
 CMailHandler::~CMailHandler()
 {
-  Clear();
 }
 
 void CMailHandler::PushMail(u32 mail, bool interrupt, int cycles_into_future)
@@ -69,7 +68,7 @@ u16 CMailHandler::ReadDSPMailboxLow()
   return 0x00;
 }
 
-void CMailHandler::Clear()
+void CMailHandler::ClearPending()
 {
   while (!m_Mails.empty())
     m_Mails.pop();
@@ -84,7 +83,7 @@ void CMailHandler::Halt(bool _Halt)
 {
   if (_Halt)
   {
-    Clear();
+    ClearPending();
     PushMail(0x80544348);
   }
 }
@@ -93,7 +92,7 @@ void CMailHandler::DoState(PointerWrap& p)
 {
   if (p.IsReadMode())
   {
-    Clear();
+    ClearPending();
     int sz = 0;
     p.Do(sz);
     for (int i = 0; i < sz; i++)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index 773cf042bb..411d169545 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -20,11 +20,15 @@ public:
 
   // TODO: figure out correct timing for interrupts rather than defaulting to "immediately."
   void PushMail(u32 mail, bool interrupt = false, int cycles_into_future = 0);
-  void Clear();
   void Halt(bool _Halt);
   void DoState(PointerWrap& p);
   bool HasPending() const;
 
+  // Clear any pending mail from the current uCode.  This is called by DSPHLE::SetUCode and
+  // DSPHLE::SwapUCode. Since pending mail is an abstraction for DSPHLE and not something that
+  // actually exists on real hardware, HLE implementations do not need to call this directly.
+  void ClearPending();
+
   u16 ReadDSPMailboxHigh();
   u16 ReadDSPMailboxLow();
 
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
index ee64a96659..45d9848b8c 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
@@ -34,7 +34,6 @@ AXUCode::AXUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 AXUCode::~AXUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void AXUCode::Initialize()
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
index 23ee74bec8..ac14bd26be 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
@@ -18,7 +18,6 @@ CARDUCode::CARDUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 CARDUCode::~CARDUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void CARDUCode::Initialize()
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
index 49816fe6fd..b22e594719 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
@@ -75,7 +75,6 @@ GBAUCode::GBAUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 GBAUCode::~GBAUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void GBAUCode::Initialize()
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
index e41a5b19c0..00e4989afe 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
@@ -34,7 +34,6 @@ ROMUCode::~ROMUCode()
 
 void ROMUCode::Initialize()
 {
-  m_mail_handler.Clear();
   m_mail_handler.PushMail(0x8071FEED);
 }
 
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
index 7cfab59596..5c07a31ea4 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
@@ -130,7 +130,6 @@ ZeldaUCode::ZeldaUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 ZeldaUCode::~ZeldaUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void ZeldaUCode::Initialize()

From 0fec8ffb3c9c71a9daaf83e5c3f8b3f7ba394583 Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Sun, 19 Jun 2022 12:19:09 -0700
Subject: [PATCH 3/6] DSPHLE: Remove empty destructors

Most of these were made unnecessary by the previous commit.
---
 Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp    | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/AX.h      | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h   | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp  | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/CARD.h    | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp   | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/GBA.h     | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp  | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/INIT.h    | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp   | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/ROM.h     | 1 -
 Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp | 4 ----
 Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h   | 1 -
 14 files changed, 35 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
index 45d9848b8c..c53d7a8e8e 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
@@ -32,10 +32,6 @@ AXUCode::AXUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "Instantiating AXUCode: crc={:08x}", crc);
 }
 
-AXUCode::~AXUCode()
-{
-}
-
 void AXUCode::Initialize()
 {
   m_mail_handler.PushMail(DSP_INIT, true);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AX.h b/Source/Core/Core/HW/DSPHLE/UCodes/AX.h
index 52adc73b63..9f69fa3195 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AX.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AX.h
@@ -66,7 +66,6 @@ class AXUCode : public UCodeInterface
 {
 public:
   AXUCode(DSPHLE* dsphle, u32 crc);
-  ~AXUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
index e1a7530c35..1c4709af16 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
@@ -30,10 +30,6 @@ AXWiiUCode::AXWiiUCode(DSPHLE* dsphle, u32 crc) : AXUCode(dsphle, crc), m_last_m
   m_old_axwii = (crc == 0xfa450138) || (crc == 0x7699af32);
 }
 
-AXWiiUCode::~AXWiiUCode()
-{
-}
-
 void AXWiiUCode::HandleCommandList()
 {
   // Temp variables for addresses computation
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h
index 7d1baf871d..27d79ba1ae 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h
@@ -15,7 +15,6 @@ class AXWiiUCode : public AXUCode
 {
 public:
   AXWiiUCode(DSPHLE* dsphle, u32 crc);
-  ~AXWiiUCode() override;
 
   void DoState(PointerWrap& p) override;
 
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
index ac14bd26be..4ad47757f8 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
@@ -16,10 +16,6 @@ CARDUCode::CARDUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "CARDUCode - initialized");
 }
 
-CARDUCode::~CARDUCode()
-{
-}
-
 void CARDUCode::Initialize()
 {
   m_mail_handler.PushMail(DSP_INIT);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h
index 99dcd2f231..55b1e7f95d 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h
@@ -14,7 +14,6 @@ class CARDUCode : public UCodeInterface
 {
 public:
   CARDUCode(DSPHLE* dsphle, u32 crc);
-  ~CARDUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
index b22e594719..bccd7fe6ef 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
@@ -73,10 +73,6 @@ GBAUCode::GBAUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 {
 }
 
-GBAUCode::~GBAUCode()
-{
-}
-
 void GBAUCode::Initialize()
 {
   m_mail_handler.PushMail(DSP_INIT);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h
index 89c9ac4af8..22083d127d 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h
@@ -18,7 +18,6 @@ void ProcessGBACrypto(u32 address);
 struct GBAUCode : public UCodeInterface
 {
   GBAUCode(DSPHLE* dsphle, u32 crc);
-  ~GBAUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp
index 6df84313f1..7869460bc1 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp
@@ -16,10 +16,6 @@ INITUCode::INITUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "INITUCode - initialized");
 }
 
-INITUCode::~INITUCode()
-{
-}
-
 void INITUCode::Initialize()
 {
   m_mail_handler.PushMail(0x80544348);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h
index 9b286065c2..53cbe01428 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h
@@ -14,7 +14,6 @@ class INITUCode : public UCodeInterface
 {
 public:
   INITUCode(DSPHLE* dsphle, u32 crc);
-  ~INITUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
index 00e4989afe..cd5e72a009 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
@@ -28,10 +28,6 @@ ROMUCode::ROMUCode(DSPHLE* dsphle, u32 crc)
   INFO_LOG_FMT(DSPHLE, "UCode_Rom - initialized");
 }
 
-ROMUCode::~ROMUCode()
-{
-}
-
 void ROMUCode::Initialize()
 {
   m_mail_handler.PushMail(0x8071FEED);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h
index bf43d34f71..431c9ed052 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h
@@ -14,7 +14,6 @@ class ROMUCode : public UCodeInterface
 {
 public:
   ROMUCode(DSPHLE* dsphle, u32 crc);
-  ~ROMUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
index 5c07a31ea4..16c5a20cda 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
@@ -128,10 +128,6 @@ ZeldaUCode::ZeldaUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "Zelda UCode loaded, crc={:08x}, flags={:08x}", crc, m_flags);
 }
 
-ZeldaUCode::~ZeldaUCode()
-{
-}
-
 void ZeldaUCode::Initialize()
 {
   if (m_flags & LIGHT_PROTOCOL)
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h
index 941f140dea..6051faf853 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h
@@ -191,7 +191,6 @@ class ZeldaUCode : public UCodeInterface
 {
 public:
   ZeldaUCode(DSPHLE* dsphle, u32 crc);
-  ~ZeldaUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;

From bdbb23fa1a3052337af2106a3dc8715a8cde8bd2 Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Wed, 8 Jun 2022 20:08:40 -0700
Subject: [PATCH 4/6] DSPHLE: Rename CMailHandler::m_Mails to m_pending_mails

---
 Source/Core/Core/HW/DSPHLE/MailHandler.cpp | 70 +++++-----------------
 Source/Core/Core/HW/DSPHLE/MailHandler.h   |  8 ++-
 2 files changed, 19 insertions(+), 59 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index b1d0377ec2..87e8d957c2 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -3,8 +3,6 @@
 
 #include "Core/HW/DSPHLE/MailHandler.h"
 
-#include <queue>
-
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
@@ -25,25 +23,25 @@ void CMailHandler::PushMail(u32 mail, bool interrupt, int cycles_into_future)
 {
   if (interrupt)
   {
-    if (m_Mails.empty())
+    if (m_pending_mails.empty())
     {
       DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP, cycles_into_future);
     }
     else
     {
-      m_Mails.front().second = true;
+      m_pending_mails.front().second = true;
     }
   }
-  m_Mails.emplace(mail, false);
+  m_pending_mails.emplace_back(mail, false);
   DEBUG_LOG_FMT(DSP_MAIL, "DSP writes {:#010x}", mail);
 }
 
 u16 CMailHandler::ReadDSPMailboxHigh()
 {
-  // check if we have a mail for the core
-  if (!m_Mails.empty())
+  // check if we have a mail for the CPU core
+  if (!m_pending_mails.empty())
   {
-    u16 result = (m_Mails.front().first >> 16) & 0xFFFF;
+    u16 result = (m_pending_mails.front().first >> 16) & 0xFFFF;
     return result;
   }
   return 0x00;
@@ -51,12 +49,12 @@ u16 CMailHandler::ReadDSPMailboxHigh()
 
 u16 CMailHandler::ReadDSPMailboxLow()
 {
-  // check if we have a mail for the core
-  if (!m_Mails.empty())
+  // check if we have a mail for the CPU core
+  if (!m_pending_mails.empty())
   {
-    u16 result = m_Mails.front().first & 0xFFFF;
-    bool generate_interrupt = m_Mails.front().second;
-    m_Mails.pop();
+    u16 result = m_pending_mails.front().first & 0xFFFF;
+    const bool generate_interrupt = m_pending_mails.front().second;
+    m_pending_mails.pop_front();
 
     if (generate_interrupt)
     {
@@ -70,13 +68,12 @@ u16 CMailHandler::ReadDSPMailboxLow()
 
 void CMailHandler::ClearPending()
 {
-  while (!m_Mails.empty())
-    m_Mails.pop();
+  m_pending_mails.clear();
 }
 
 bool CMailHandler::HasPending() const
 {
-  return !m_Mails.empty();
+  return !m_pending_mails.empty();
 }
 
 void CMailHandler::Halt(bool _Halt)
@@ -90,45 +87,6 @@ void CMailHandler::Halt(bool _Halt)
 
 void CMailHandler::DoState(PointerWrap& p)
 {
-  if (p.IsReadMode())
-  {
-    ClearPending();
-    int sz = 0;
-    p.Do(sz);
-    for (int i = 0; i < sz; i++)
-    {
-      u32 mail = 0;
-      bool interrupt = false;
-      p.Do(mail);
-      p.Do(interrupt);
-      m_Mails.emplace(mail, interrupt);
-    }
-  }
-  else  // WRITE and MEASURE
-  {
-    std::queue<std::pair<u32, bool>> temp;
-    int sz = (int)m_Mails.size();
-    p.Do(sz);
-    for (int i = 0; i < sz; i++)
-    {
-      u32 value = m_Mails.front().first;
-      bool interrupt = m_Mails.front().second;
-      m_Mails.pop();
-      p.Do(value);
-      p.Do(interrupt);
-      temp.emplace(value, interrupt);
-    }
-    if (!m_Mails.empty())
-      PanicAlertFmt("CMailHandler::DoState - WTF?");
-
-    // Restore queue.
-    for (int i = 0; i < sz; i++)
-    {
-      u32 value = temp.front().first;
-      bool interrupt = temp.front().second;
-      temp.pop();
-      m_Mails.emplace(value, interrupt);
-    }
-  }
+  p.Do(m_pending_mails);
 }
 }  // namespace DSP::HLE
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index 411d169545..0bc1227ede 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include <queue>
+#include <deque>
 #include <utility>
 
 #include "Common/CommonTypes.h"
@@ -33,7 +33,9 @@ public:
   u16 ReadDSPMailboxLow();
 
 private:
-  // mail handler
-  std::queue<std::pair<u32, bool>> m_Mails;
+  // The actual DSP only has a single pair of mail registers, and doesn't keep track of pending
+  // mails. But for HLE, it's a lot easier to write all the mails that will be read ahead of time,
+  // and then give them to the CPU in the requested order.
+  std::deque<std::pair<u32, bool>> m_pending_mails;
 };
 }  // namespace DSP::HLE

From 3aeafcc70b4358d0a9736d5c654fd8b9e30e4ead Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Thu, 16 Jun 2022 14:51:59 -0700
Subject: [PATCH 5/6] DSPHLE: Return last mail with top bit cleared if there is
 no new mail

This is an accuracy improvement, though I don't think it matters for anything in practice.
---
 Source/Core/Core/HW/DSPHLE/MailHandler.cpp | 17 ++++++++++-------
 Source/Core/Core/HW/DSPHLE/MailHandler.h   |  5 +++++
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index 87e8d957c2..fc5b22b778 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -41,10 +41,9 @@ u16 CMailHandler::ReadDSPMailboxHigh()
   // check if we have a mail for the CPU core
   if (!m_pending_mails.empty())
   {
-    u16 result = (m_pending_mails.front().first >> 16) & 0xFFFF;
-    return result;
+    m_last_mail = m_pending_mails.front().first;
   }
-  return 0x00;
+  return u16(m_last_mail >> 0x10);
 }
 
 u16 CMailHandler::ReadDSPMailboxLow()
@@ -52,18 +51,22 @@ u16 CMailHandler::ReadDSPMailboxLow()
   // check if we have a mail for the CPU core
   if (!m_pending_mails.empty())
   {
-    u16 result = m_pending_mails.front().first & 0xFFFF;
+    m_last_mail = m_pending_mails.front().first;
     const bool generate_interrupt = m_pending_mails.front().second;
+
     m_pending_mails.pop_front();
 
     if (generate_interrupt)
     {
       DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP);
     }
-
-    return result;
   }
-  return 0x00;
+  // Clear the top bit of the high mail word after the mail has been read.
+  // The remaining bits read back the same as the previous mail, until new mail sent.
+  // (The CPU reads the high word first, and then the low word; since this function returns the low
+  // word, this means that the next read of the high word will have the top bit cleared.)
+  m_last_mail &= ~0x8000'0000;
+  return u16(m_last_mail & 0xffff);
 }
 
 void CMailHandler::ClearPending()
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index 0bc1227ede..c036a9f72d 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -27,6 +27,8 @@ public:
   // Clear any pending mail from the current uCode.  This is called by DSPHLE::SetUCode and
   // DSPHLE::SwapUCode. Since pending mail is an abstraction for DSPHLE and not something that
   // actually exists on real hardware, HLE implementations do not need to call this directly.
+  // Note that this function does not reset m_last_mail, which will continue to read the same value
+  // until the new uCode sends mail.
   void ClearPending();
 
   u16 ReadDSPMailboxHigh();
@@ -37,5 +39,8 @@ private:
   // mails. But for HLE, it's a lot easier to write all the mails that will be read ahead of time,
   // and then give them to the CPU in the requested order.
   std::deque<std::pair<u32, bool>> m_pending_mails;
+  // If no pending mail exists, the last mail that was read is returned,
+  // but with the top bit (0x80000000) cleared.
+  u32 m_last_mail = 0;
 };
 }  // namespace DSP::HLE

From a72fa4b9ccabf5113a903f880e7df64e9dffc467 Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Thu, 16 Jun 2022 15:40:41 -0700
Subject: [PATCH 6/6] DSPHLE: Don't generate new mail if the DSP is halted

This fixes booting Datel titles with DSPHLE (see https://bugs.dolphin-emu.org/issues/12943). Datel messed up their DSP initialization code, so it only works by receiving a mail later on, but if halting isn't implemented then it receives the mail too early and hangs.
---
 Source/Core/Core/HW/DSPHLE/DSPHLE.cpp      |  1 +
 Source/Core/Core/HW/DSPHLE/MailHandler.cpp | 12 ++++--------
 Source/Core/Core/HW/DSPHLE/MailHandler.h   |  4 +++-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
index 9e17a78ecc..b8d3b8e5a2 100644
--- a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
+++ b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
@@ -196,6 +196,7 @@ u16 DSPHLE::DSP_WriteControlRegister(u16 value)
   {
     INFO_LOG_FMT(DSPHLE, "DSP_CONTROL halt bit changed: {:04x} -> {:04x}", m_dsp_control.Hex,
                  value);
+    m_mail_handler.SetHalted(temp.DSPHalt);
   }
 
   if (temp.DSPReset)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index fc5b22b778..f297b6f53c 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -39,7 +39,7 @@ void CMailHandler::PushMail(u32 mail, bool interrupt, int cycles_into_future)
 u16 CMailHandler::ReadDSPMailboxHigh()
 {
   // check if we have a mail for the CPU core
-  if (!m_pending_mails.empty())
+  if (!m_halted && !m_pending_mails.empty())
   {
     m_last_mail = m_pending_mails.front().first;
   }
@@ -49,7 +49,7 @@ u16 CMailHandler::ReadDSPMailboxHigh()
 u16 CMailHandler::ReadDSPMailboxLow()
 {
   // check if we have a mail for the CPU core
-  if (!m_pending_mails.empty())
+  if (!m_halted && !m_pending_mails.empty())
   {
     m_last_mail = m_pending_mails.front().first;
     const bool generate_interrupt = m_pending_mails.front().second;
@@ -79,13 +79,9 @@ bool CMailHandler::HasPending() const
   return !m_pending_mails.empty();
 }
 
-void CMailHandler::Halt(bool _Halt)
+void CMailHandler::SetHalted(bool halt)
 {
-  if (_Halt)
-  {
-    ClearPending();
-    PushMail(0x80544348);
-  }
+  m_halted = halt;
 }
 
 void CMailHandler::DoState(PointerWrap& p)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index c036a9f72d..ee38bcde53 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -20,7 +20,7 @@ public:
 
   // TODO: figure out correct timing for interrupts rather than defaulting to "immediately."
   void PushMail(u32 mail, bool interrupt = false, int cycles_into_future = 0);
-  void Halt(bool _Halt);
+  void SetHalted(bool halt);
   void DoState(PointerWrap& p);
   bool HasPending() const;
 
@@ -42,5 +42,7 @@ private:
   // If no pending mail exists, the last mail that was read is returned,
   // but with the top bit (0x80000000) cleared.
   u32 m_last_mail = 0;
+  // When halted, the DSP itself is not running, but the last mail can be read.
+  bool m_halted = false;
 };
 }  // namespace DSP::HLE