Rename to DuckStation

src/core/digital_controller.cpp

@@ -0,0 +1,83 @@
+#include "digital_controller.h"
+#include "YBaseLib/Log.h"
+Log_SetChannel(DigitalController);
+
+DigitalController::DigitalController() = default;
+
+DigitalController::~DigitalController() = default;
+
+void DigitalController::SetButtonState(Button button, bool pressed)
+{
+  if (pressed)
+    m_button_state &= ~(u16(1) << static_cast<u8>(button));
+  else
+    m_button_state |= u16(1) << static_cast<u8>(button);
+}
+
+void DigitalController::ResetTransferState()
+{
+  m_transfer_fifo.Clear();
+}
+
+bool DigitalController::Transfer(const u8 data_in, u8* data_out)
+{
+  bool ack;
+
+  switch (data_in)
+  {
+    case 0x01: // tests if the controller is present
+    {
+      Log_DebugPrintf("Access");
+
+      // response is hi-z
+      *data_out = 0xFF;
+      ack = true;
+    }
+    break;
+
+    case 0x42: // query state
+    {
+      Log_DebugPrintf("Query state");
+      QueryState();
+      [[fallthrough]];
+    }
+
+    default: // sending response
+    {
+      if (m_transfer_fifo.IsEmpty())
+      {
+        Log_WarningPrint("FIFO empty on read");
+        *data_out = 0xFF;
+        ack = false;
+      }
+      else
+      {
+        *data_out = m_transfer_fifo.Pop();
+        ack = !m_transfer_fifo.IsEmpty();
+      }
+    }
+    break;
+  }
+
+  Log_DebugPrintf("Transfer, data_in=0x%02X, data_out=0x%02X, ack=%s", data_in, *data_out, ack ? "true" : "false");
+  return ack;
+}
+
+void DigitalController::QueryState()
+{
+  constexpr u16 ID = 0x5A41;
+
+  m_transfer_fifo.Clear();
+
+  m_transfer_fifo.Push(Truncate8(ID));
+  m_transfer_fifo.Push(Truncate8(ID >> 8));
+
+  m_transfer_fifo.Push(Truncate8(m_button_state));      // Digital switches low
+  m_transfer_fifo.Push(Truncate8(m_button_state >> 8)); // Digital switches high
+}
+
+std::shared_ptr<DigitalController> DigitalController::Create()
+{
+  return std::make_shared<DigitalController>();
+}
+