From 329e8317b4939911a3276c68777de0e3a4f74a7a Mon Sep 17 00:00:00 2001
From: Albert Liu <45282415+ggrtk@users.noreply.github.com>
Date: Sun, 21 Feb 2021 15:20:31 -0800
Subject: [PATCH] Controller: Always check for access byte

---
 src/core/analog_controller.cpp  | 27 ++++++++++++++++++---------
 src/core/analog_controller.h    |  1 +
 src/core/analog_joystick.cpp    | 21 +++++++++++++++------
 src/core/analog_joystick.h      |  1 +
 src/core/digital_controller.cpp | 21 +++++++++++++++------
 src/core/digital_controller.h   |  1 +
 src/core/namco_guncon.cpp       | 21 +++++++++++++++------
 src/core/namco_guncon.h         |  1 +
 src/core/negcon.cpp             | 20 +++++++++++++++-----
 src/core/negcon.h               |  3 ++-
 src/core/playstation_mouse.cpp  | 21 +++++++++++++++------
 src/core/playstation_mouse.h    |  1 +
 12 files changed, 100 insertions(+), 39 deletions(-)

diff --git a/src/core/analog_controller.cpp b/src/core/analog_controller.cpp
index d0516e995..58dccc3b3 100644
--- a/src/core/analog_controller.cpp
+++ b/src/core/analog_controller.cpp
@@ -314,6 +314,22 @@ bool AnalogController::Transfer(const u8 data_in, u8* data_out)
   switch (m_command)
   {
     case Command::Idle:
+    {
+      *data_out = 0xFF;
+
+      if (data_in == 0x01)
+      {
+        Log_DevPrintf("ACK controller access");
+        m_command = Command::Ready;
+        return true;
+      }
+
+      Log_DevPrintf("Unknown data_in = 0x%02X", data_in);
+      return false;
+    }
+    break;
+
+    case Command::Ready:
     {
       if (data_in == 0x42)
       {
@@ -378,15 +394,8 @@ bool AnalogController::Transfer(const u8 data_in, u8* data_out)
       }
       else
       {
-        *data_out = 0xFF;
-        ack = (data_in == 0x01);
-
-        if (ack)
-          Log_DevPrintf("ACK controller access");
-        else
-          Log_DevPrintf("Unknown data_in = 0x%02X", data_in);
-
-        return ack;
+        Log_ErrorPrintf("Unimplemented analog controller command 0x%02X", data_in);
+        Panic("Unimplemented analog controller command");
       }
     }
     break;
diff --git a/src/core/analog_controller.h b/src/core/analog_controller.h
index 0091444f4..fdd45ae0b 100644
--- a/src/core/analog_controller.h
+++ b/src/core/analog_controller.h
@@ -81,6 +81,7 @@ private:
   enum class Command : u8
   {
     Idle,
+    Ready,
     ReadPad,           // 0x42
     ConfigModeSetMode, // 0x43
     SetAnalogMode,     // 0x44
diff --git a/src/core/analog_joystick.cpp b/src/core/analog_joystick.cpp
index 398d10ac9..b47e88760 100644
--- a/src/core/analog_joystick.cpp
+++ b/src/core/analog_joystick.cpp
@@ -167,18 +167,27 @@ bool AnalogJoystick::Transfer(const u8 data_in, u8* data_out)
   {
     case TransferState::Idle:
     {
-      // ack when sent 0x01, send ID for 0x42
+      *data_out = 0xFF;
+
+      if (data_in == 0x01)
+      {
+        m_transfer_state = TransferState::Ready;
+        return true;
+      }
+      return false;
+    }
+
+    case TransferState::Ready:
+    {
       if (data_in == 0x42)
       {
         *data_out = Truncate8(GetID());
         m_transfer_state = TransferState::IDMSB;
         return true;
       }
-      else
-      {
-        *data_out = 0xFF;
-        return (data_in == 0x01);
-      }
+
+      *data_out = 0xFF;
+      return false;
     }
 
     case TransferState::IDMSB:
diff --git a/src/core/analog_joystick.h b/src/core/analog_joystick.h
index 5816f3b2d..b5bf0d414 100644
--- a/src/core/analog_joystick.h
+++ b/src/core/analog_joystick.h
@@ -71,6 +71,7 @@ private:
   enum class TransferState : u8
   {
     Idle,
+    Ready,
     IDMSB,
     ButtonsLSB,
     ButtonsMSB,
diff --git a/src/core/digital_controller.cpp b/src/core/digital_controller.cpp
index 389c5f91b..3563499ca 100644
--- a/src/core/digital_controller.cpp
+++ b/src/core/digital_controller.cpp
@@ -89,18 +89,27 @@ bool DigitalController::Transfer(const u8 data_in, u8* data_out)
   {
     case TransferState::Idle:
     {
-      // ack when sent 0x01, send ID for 0x42
+      *data_out = 0xFF;
+
+      if (data_in == 0x01)
+      {
+        m_transfer_state = TransferState::Ready;
+        return true;
+      }
+      return false;
+    }
+
+    case TransferState::Ready:
+    {
       if (data_in == 0x42)
       {
         *data_out = Truncate8(ID);
         m_transfer_state = TransferState::IDMSB;
         return true;
       }
-      else
-      {
-        *data_out = 0xFF;
-        return (data_in == 0x01);
-      }
+
+      *data_out = 0xFF;
+      return false;
     }
 
     case TransferState::IDMSB:
diff --git a/src/core/digital_controller.h b/src/core/digital_controller.h
index 69f4ebd7e..d57b91331 100644
--- a/src/core/digital_controller.h
+++ b/src/core/digital_controller.h
@@ -61,6 +61,7 @@ private:
   enum class TransferState : u8
   {
     Idle,
+    Ready,
     IDMSB,
     ButtonsLSB,
     ButtonsMSB
diff --git a/src/core/namco_guncon.cpp b/src/core/namco_guncon.cpp
index 8e508e572..7a0104cba 100644
--- a/src/core/namco_guncon.cpp
+++ b/src/core/namco_guncon.cpp
@@ -95,18 +95,27 @@ bool NamcoGunCon::Transfer(const u8 data_in, u8* data_out)
   {
     case TransferState::Idle:
     {
-      // ack when sent 0x01, send ID for 0x42
+      *data_out = 0xFF;
+
+      if (data_in == 0x01)
+      {
+        m_transfer_state = TransferState::Ready;
+        return true;
+      }
+      return false;
+    }
+
+    case TransferState::Ready:
+    {
       if (data_in == 0x42)
       {
         *data_out = Truncate8(ID);
         m_transfer_state = TransferState::IDMSB;
         return true;
       }
-      else
-      {
-        *data_out = 0xFF;
-        return (data_in == 0x01);
-      }
+
+      *data_out = 0xFF;
+      return false;
     }
 
     case TransferState::IDMSB:
diff --git a/src/core/namco_guncon.h b/src/core/namco_guncon.h
index a316f8b55..eba8edf6f 100644
--- a/src/core/namco_guncon.h
+++ b/src/core/namco_guncon.h
@@ -50,6 +50,7 @@ private:
   enum class TransferState : u8
   {
     Idle,
+    Ready,
     IDMSB,
     ButtonsLSB,
     ButtonsMSB,
diff --git a/src/core/negcon.cpp b/src/core/negcon.cpp
index 65e95ebc0..1d286dcfb 100644
--- a/src/core/negcon.cpp
+++ b/src/core/negcon.cpp
@@ -120,6 +120,18 @@ bool NeGcon::Transfer(const u8 data_in, u8* data_out)
   switch (m_transfer_state)
   {
     case TransferState::Idle:
+    {
+      *data_out = 0xFF;
+
+      if (data_in == 0x01)
+      {
+        m_transfer_state = TransferState::Ready;
+        return true;
+      }
+      return false;
+    }
+
+    case TransferState::Ready:
     {
       if (data_in == 0x42)
       {
@@ -127,11 +139,9 @@ bool NeGcon::Transfer(const u8 data_in, u8* data_out)
         m_transfer_state = TransferState::IDMSB;
         return true;
       }
-      else
-      {
-        *data_out = 0xFF;
-        return (data_in == 0x01);
-      }
+
+      *data_out = 0xFF;
+      return false;
     }
 
     case TransferState::IDMSB:
diff --git a/src/core/negcon.h b/src/core/negcon.h
index 819678166..6f5746173 100644
--- a/src/core/negcon.h
+++ b/src/core/negcon.h
@@ -66,6 +66,7 @@ private:
   enum class TransferState : u8
   {
     Idle,
+    Ready,
     IDMSB,
     ButtonsLSB,
     ButtonsMSB,
@@ -75,7 +76,7 @@ private:
     AnalogL
   };
 
-  std::array<u8, static_cast<u8>(Axis::Count)> m_axis_state {};
+  std::array<u8, static_cast<u8>(Axis::Count)> m_axis_state{};
 
   // buttons are active low; bits 0-2, 8-10, 14-15 are not used and are always high
   u16 m_button_state = UINT16_C(0xFFFF);
diff --git a/src/core/playstation_mouse.cpp b/src/core/playstation_mouse.cpp
index 57c4eeb2b..a689d61d2 100644
--- a/src/core/playstation_mouse.cpp
+++ b/src/core/playstation_mouse.cpp
@@ -91,18 +91,27 @@ bool PlayStationMouse::Transfer(const u8 data_in, u8* data_out)
   {
     case TransferState::Idle:
     {
-      // ack when sent 0x01, send ID for 0x42
+      *data_out = 0xFF;
+
+      if (data_in == 0x01)
+      {
+        m_transfer_state = TransferState::Ready;
+        return true;
+      }
+      return false;
+    }
+
+    case TransferState::Ready:
+    {
       if (data_in == 0x42)
       {
         *data_out = Truncate8(ID);
         m_transfer_state = TransferState::IDMSB;
         return true;
       }
-      else
-      {
-        *data_out = 0xFF;
-        return (data_in == 0x01);
-      }
+
+      *data_out = 0xFF;
+      return false;
     }
 
     case TransferState::IDMSB:
diff --git a/src/core/playstation_mouse.h b/src/core/playstation_mouse.h
index c47f3501d..ecfc4abfd 100644
--- a/src/core/playstation_mouse.h
+++ b/src/core/playstation_mouse.h
@@ -49,6 +49,7 @@ private:
   enum class TransferState : u8
   {
     Idle,
+    Ready,
     IDMSB,
     ButtonsLSB,
     ButtonsMSB,