[Simh] DOSBox Terminal emulator break, msKermit 3.15

[Rodney Brown]

With the attached patch DOSBox will support BREAK over nullmodem or 
modem (telnet) connections.

Tested with msKermit 3.15 connecting to the HP3000 emulator
(Alt-B, Ctrl-] L )

The DOS HP Terminal Program (Manual 24597-90002 Nov 1988) worked 
(Shift-Break)
as did HP AdvanceLink 2392 ~1986. (Alt-F1)

Using DOSBox

serial1 nullmodem server:127.0.0.1 port:1054

rather than

serial1 modem
and connecting with the Hayes style command.
ATD 127.0.0.1 port:1054

seemed to be more stable.
-------------- next part --------------
diff --git a/src/hardware/serialport/nullmodem.cpp b/src/hardware/serialport/nullmodem.cpp
index 2865073..396bf2e 100644
--- a/src/hardware/serialport/nullmodem.cpp
+++ b/src/hardware/serialport/nullmodem.cpp
@@ -177,8 +177,8 @@ Bits CNullModem::readChar() {
 		// get the next char
 		Bits rxchar = clientsocket->GetcharNonBlock();
 		if (rxchar==0xff) return rxchar; // 0xff 0xff -> 0xff was meant
-		rxchar&0x1? setCTS(true) : setCTS(false);
-		rxchar&0x2? setDSR(true) : setDSR(false);
+		setCTS((rxchar&0x1) != 0);
+		setDSR((rxchar&0x2) != 0);
 		if (rxchar&0x4) receiveByteEx(0x0,0x10);
 		return -1;	// no "payload" received
 	} else return rxchar;
@@ -561,8 +561,16 @@ Bits CNullModem::TelnetEmulation(Bit8u data) {
 /* setBreak(val) switches break on or off                                   **/
 /*****************************************************************************/
 
-void CNullModem::setBreak (bool /*value*/) {
-	CNullModem::setRTSDTR(getRTS(), getDTR());
+void CNullModem::setBreak (bool value) {
+	if (!clientsocket)
+	    CNullModem::setRTSDTR(getRTS(), getDTR());
+	else if (value) {
+	    Bit8u response[2];
+
+	    response[0]=0xff;	/* IAC */
+	    response[1]=243;	/* BREAK: NVT character BRK */
+	    clientsocket->SendArray(response, 2);
+	}
 }
 
 /*****************************************************************************/
diff --git a/src/hardware/serialport/softmodem.cpp b/src/hardware/serialport/softmodem.cpp
index d135b8f..34d81a1 100644
--- a/src/hardware/serialport/softmodem.cpp
+++ b/src/hardware/serialport/softmodem.cpp
@@ -796,8 +796,17 @@ void CSerialModem::updateMSR() {
 	// think it is not needed
 }
 
-void CSerialModem::setBreak(bool) {
+void CSerialModem::setBreak(bool value) {
 	// TODO: handle this
+	if (!clientsocket)
+	    ;	// TODO: handle this
+	else if (value) {
+	    Bit8u response[2];
+
+	    response[0]=0xff;	/* IAC */
+	    response[1]=243;	/* BREAK: NVT character BRK */
+	    clientsocket->SendArray(response, 2);
+	}
 }
 
 void CSerialModem::setRTSDTR(bool rts, bool dtr) {