From abd99d109e5319235294b486b268cf68c47a134b Mon Sep 17 00:00:00 2001
From: tomcw <tomcw@users.noreply.github.com>
Date: Sun, 19 Mar 2017 21:44:20 +0000
Subject: [PATCH] SSC: Experimental support for 6551's status bits: DCD and DSR
 via -dcd[-invert] and -dsr[-invert] args (#386)

---
 source/Applewin.cpp    | 16 ++++++++++++++++
 source/SerialComms.cpp | 36 +++++++++++++++++++++++++++---------
 source/SerialComms.h   | 12 +++++++++++-
 3 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/source/Applewin.cpp b/source/Applewin.cpp
index c1d76cf6..ff8e197d 100644
--- a/source/Applewin.cpp
+++ b/source/Applewin.cpp
@@ -1034,6 +1034,22 @@ int APIENTRY WinMain(HINSTANCE passinstance, HINSTANCE, LPSTR lpCmdLine, int)
 		{
 			g_bMultiMon = true;
 		}
+		else if (strcmp(lpCmdLine, "-dcd") == 0)	// GH#386
+		{
+			sg_SSC.SupportDCD(true, false);
+		}
+		else if (strcmp(lpCmdLine, "-dcd-invert") == 0)	// GH#386
+		{
+			sg_SSC.SupportDCD(true, true);
+		}
+		else if (strcmp(lpCmdLine, "-dsr") == 0)	// GH#386
+		{
+			sg_SSC.SupportDSR(true, false);
+		}
+		else if (strcmp(lpCmdLine, "-dsr-invert") == 0)	// GH#386
+		{
+			sg_SSC.SupportDSR(true, true);
+		}
 		else if (strcmp(lpCmdLine, "-dtr") == 0)	// GH#386
 		{
 			sg_SSC.SupportDTR(true, false);
diff --git a/source/SerialComms.cpp b/source/SerialComms.cpp
index cc89be08..075c1c27 100644
--- a/source/SerialComms.cpp
+++ b/source/SerialComms.cpp
@@ -721,10 +721,12 @@ BYTE __stdcall CSuperSerialCard::CommStatus(WORD, WORD, BYTE, BYTE, ULONG)
 	if (!CheckComm())
 		return ST_DSR | ST_DCD | ST_TX_EMPTY;
 
-#ifdef SUPPORT_MODEM
-	DWORD modemstatus = 0;
-	GetCommModemStatus(m_hCommHandle,&modemstatus);				// Returns 0x30 = MS_DSR_ON|MS_CTS_ON
-#endif
+	DWORD modemStatus = 0;
+	if ((m_hCommHandle != INVALID_HANDLE_VALUE) && (m_bCfgSupportDCD || m_bCfgSupportDSR))
+	{
+		// Do this outside of the critical section (don't know how long it takes)
+		GetCommModemStatus(m_hCommHandle, &modemStatus);	// Returns 0x30 = MS_DSR_ON|MS_CTS_ON
+	}
 
 	//
 
@@ -757,13 +759,29 @@ BYTE __stdcall CSuperSerialCard::CommStatus(WORD, WORD, BYTE, BYTE, ULONG)
 
 	//
 
+	BYTE DCD = 0;
+	BYTE DSR = 0;
+
+	if ((m_hCommHandle != INVALID_HANDLE_VALUE) && (m_bCfgSupportDCD || m_bCfgSupportDSR))
+	{
+		if (m_bCfgSupportDCD)
+		{
+			DCD = (modemStatus & MS_RLSD_ON) ? 0x00 : ST_DCD;
+			if (m_bCfgInvertDCD) DCD = (DCD == 0) ? ST_DCD : 0;
+		}
+
+		if (m_bCfgSupportDSR)
+		{
+			DSR = (modemStatus & MS_DSR_ON)	 ? 0x00 : ST_DSR;
+			if (m_bCfgInvertDSR) DSR = (DSR == 0) ? ST_DSR : 0;
+		}
+	}
+
 	BYTE uStatus = ST_TX_EMPTY 
 				| ((!bComSerialBufferEmpty || !m_qTcpSerialBuffer.empty()) ? ST_RX_FULL : 0x00)
-#ifdef SUPPORT_MODEM
-				| ((modemstatus & MS_RLSD_ON)	? 0x00 : ST_DCD)	// Need 0x00 to allow ZLink to start up
-				| ((modemstatus & MS_DSR_ON)	? 0x00 : ST_DSR)
-#endif
-				| (bIRQ							? ST_IRQ : 0x00);
+				| DCD										// Need 0x00 to allow ZLink to start up
+				| DSR
+				| (bIRQ	? ST_IRQ : 0x00);
 
 	if (m_hCommHandle != INVALID_HANDLE_VALUE)
 	{
diff --git a/source/SerialComms.h b/source/SerialComms.h
index 036486bb..bfa06e8a 100644
--- a/source/SerialComms.h
+++ b/source/SerialComms.h
@@ -43,7 +43,9 @@ public:
 	char*	GetSerialPortName() { return m_ayCurrentSerialPortName; }
 	void	SetSerialPortName(const char* pSerialPortName);
 	bool	IsActive() { return (m_hCommHandle != INVALID_HANDLE_VALUE) || (m_hCommListenSocket != INVALID_SOCKET); }
-	void	SupportDTR(bool bEnable, bool bInvert) { m_bCfgSupportDTR = bEnable; m_bCfgInvertDTR = bInvert; }
+	void	SupportDCD(bool bEnable, bool bInvert) { m_bCfgSupportDCD = bEnable; m_bCfgInvertDCD = bInvert; }	// Status
+	void	SupportDSR(bool bEnable, bool bInvert) { m_bCfgSupportDSR = bEnable; m_bCfgInvertDSR = bInvert; }	// Status
+	void	SupportDTR(bool bEnable, bool bInvert) { m_bCfgSupportDTR = bEnable; m_bCfgInvertDTR = bInvert; }	// Control
 
 	void	CommTcpSerialAccept();
 	void	CommTcpSerialReceive();
@@ -141,6 +143,14 @@ private:
 	BYTE* m_pExpansionRom;
 	UINT m_uSlot;
 
+	// DCD
+	bool m_bCfgSupportDCD;
+	bool m_bCfgInvertDCD;
+
+	// DSR
+	bool m_bCfgSupportDSR;
+	bool m_bCfgInvertDSR;
+
 	// DTR
 	UINT	m_uDTR;
 	bool m_bCfgSupportDTR;