CDROM: Implement get version and getstat commands

src/pse/cdrom.cpp

@@ -1,6 +1,7 @@
 #include "cdrom.h"
 #include "YBaseLib/Log.h"
 #include "common/state_wrapper.h"
+#include "interrupt_controller.h"
 Log_SetChannel(CDROM);
 
 CDROM::CDROM() = default;
@@ -16,9 +17,17 @@ bool CDROM::Initialize(DMA* dma, InterruptController* interrupt_controller)
 
 void CDROM::Reset()
 {
+  m_state = State::Idle;
+  m_status.bits = 0;
+  m_secondary_status.bits = 0;
+  m_interrupt_enable_register = INTERRUPT_REGISTER_MASK;
+  m_interrupt_flag_register = 0;
   m_param_fifo.Clear();
   m_response_fifo.Clear();
   m_data_fifo.Clear();
+  UpdateStatusRegister();
+
+  m_secondary_status.shell_open = true;
 }
 
 bool CDROM::DoState(StateWrapper& sw)
@@ -39,10 +48,18 @@ u8 CDROM::ReadRegister(u32 offset)
       return m_status.bits;
 
     case 1: // always response FIFO
-      return m_response_fifo.Pop();
+    {
+      const u8 value = m_response_fifo.Pop();
+      UpdateStatusRegister();
+      return value;
+    }
 
     case 2: // always data FIFO
-      return m_data_fifo.Pop();
+    {
+      const u8 value = m_data_fifo.Pop();
+      UpdateStatusRegister();
+      return value;
+    }
 
     case 3:
     {
@@ -88,7 +105,7 @@ void CDROM::WriteRegister(u32 offset, u8 value)
           if (m_state != State::Idle)
             Log_ErrorPrintf("Ignoring write (0x%02X) to command register in non-idle state", ZeroExtend32(value));
           else
-            WriteCommand(value);
+            ExecuteCommand(static_cast<Command>(value));
 
           return;
         }
@@ -127,6 +144,7 @@ void CDROM::WriteRegister(u32 offset, u8 value)
           }
 
           m_param_fifo.Push(value);
+          UpdateStatusRegister();
           return;
         }
 
@@ -190,9 +208,74 @@ void CDROM::WriteRegister(u32 offset, u8 value)
                   ZeroExtend32(m_status.index.GetValue()), ZeroExtend32(value));
 }
 
+void CDROM::SetInterrupt(Interrupt interrupt)
+{
+  m_interrupt_flag_register = static_cast<u8>(interrupt);
+  if (HasPendingInterrupt())
+    m_interrupt_controller->InterruptRequest(InterruptController::IRQ::CDROM);
+}
+
+void CDROM::UpdateStatusRegister()
+{
+  m_status.ADPBUSY = false;
+  m_status.PRMEMPTY = m_param_fifo.IsEmpty();
+  m_status.PRMWRDY = m_param_fifo.IsFull();
+  m_status.RSLRRDY = !m_response_fifo.IsEmpty();
+  m_status.DRQSTS = !m_data_fifo.IsEmpty();
+  m_status.BUSYSTS = m_state != State::Idle;
+}
+
 void CDROM::Execute() {}
 
-void CDROM::WriteCommand(u8 command)
+void CDROM::ExecuteCommand(Command command)
 {
-  Log_ErrorPrintf("CDROM write command 0x%02X", ZeroExtend32(command));
+  Log_ErrorPrintf("CDROM write command 0x%02X", ZeroExtend32(static_cast<u8>(command)));
+
+  switch (command)
+  {
+    case Command::Getstat:
+    {
+      Log_DebugPrintf("CDROM Getstat command");
+
+      // if bit 0 or 2 is set, send an additional byte
+      m_response_fifo.Push(m_secondary_status.bits);
+      SetInterrupt(Interrupt::INT3);
+      UpdateStatusRegister();
+    }
+    break;
+
+    case Command::Test:
+    {
+      const u8 subcommand = m_param_fifo.Pop();
+      ExecuteTestCommand(subcommand);
+    }
+    break;
+
+    default:
+      Panic("Unknown command");
+      break;
+  }
+}
+
+void CDROM::ExecuteTestCommand(u8 subcommand)
+{
+  switch (subcommand)
+  {
+    case 0x20: // Get CDROM BIOS Date/Version
+    {
+      Log_DebugPrintf("Get CDROM BIOS Date/Version");
+      static constexpr u8 response[] = {0x94, 0x09, 0x19, 0xC0};
+      m_response_fifo.PushRange(response, countof(response));
+      m_param_fifo.Clear();
+      SetInterrupt(Interrupt::INT3);
+      UpdateStatusRegister();
+      return;
+    }
+
+    default:
+    {
+      Log_ErrorPrintf("Unknown test command 0x%02X", subcommand);
+      return;
+    }
+  }
 }