delphi/KPCOMM.PAS

@@ -351,6 +351,7 @@ end;
 
 function TKPComm.GetInput: string;
 var
+  Stat:        TComStat;
   BytesToRead: Integer;
   BytesRead:   Integer;
   Buf:         array[0..255] of Char;
@@ -359,12 +360,15 @@ begin
   if not FPortOpen or (FCommId < 0) then
     Exit;
 
-  { Read directly without querying GetCommError first.  ReadComm      }
-  { returns the number of bytes actually available (up to BytesToRead) }
-  { so the extra GetCommError round-trip is unnecessary overhead.      }
-  BytesToRead := 255;
+  GetCommError(FCommId, Stat);
+  BytesToRead := Stat.cbInQue;
+
   if (FInputLen > 0) and (BytesToRead > FInputLen) then
     BytesToRead := FInputLen;
+  if BytesToRead > 255 then
+    BytesToRead := 255;
+  if BytesToRead <= 0 then
+    Exit;
 
   BytesRead := ReadComm(FCommId, @Buf, BytesToRead);
   if BytesRead <= 0 then
@@ -554,12 +558,14 @@ end;
 
 
 procedure TKPComm.ProcessReceiveNotify;
+var
+  Stat: TComStat;
 begin
   if FRThreshold <= 0 then
     Exit;
-  { WM_COMMNOTIFY with CN_RECEIVE means data is available -- the driver }
-  { already checked the threshold.  No need to call GetCommError here.  }
-  DoCommEvent(comEvReceive);
+  GetCommError(FCommId, Stat);
+  if Integer(Stat.cbInQue) >= FRThreshold then
+    DoCommEvent(comEvReceive);
 end;
 
 

delphi/README.md

@@ -116,9 +116,6 @@ CSI (ESC\[) sequences:
 | ESC\[*params*m | SGR | Set graphic rendition (see below) |
 | ESC\[s | SCP | Save cursor position |
 | ESC\[u | RCP | Restore cursor position |
-| ESC\[c | DA | Device Attributes — responds ESC\[?1;0c (VT100) |
-| ESC\[5n | DSR | Device Status Report — responds ESC\[0n (OK) |
-| ESC\[6n | CPR | Cursor Position Report — responds ESC\[*row*;*col*R |
 
 SGR codes:
 
@@ -151,7 +148,6 @@ Control characters:
 | LF (#10) | Line feed (scrolls at bottom) |
 | BS (#8) | Backspace (no erase) |
 | TAB (#9) | Tab to next 8-column stop |
-| ENQ (#5) | Answerback — responds ESC\[?1;0c (VT100) |
 | BEL (#7) | System beep |
 
 **ANSI Music:**

delphi/TESTMAIN.PAS

@@ -85,19 +85,9 @@ begin
   case FComm.CommEvent of
     comEvReceive:
       begin
-        { Drain all available data in a single update batch.  This    }
-        { suppresses per-Write rendering so we get one paint at the   }
-        { end instead of one per 255-byte chunk.                      }
-        FAnsi.BeginUpdate;
-        try
-          repeat
-            S := FComm.Input;
-            if Length(S) > 0 then
-              FAnsi.Write(S);
-          until Length(S) = 0;
-        finally
-          FAnsi.EndUpdate;
-        end;
+        S := FComm.Input;
+        if Length(S) > 0 then
+          FAnsi.Write(S);
       end;
   end;
 end;
@@ -141,7 +131,7 @@ begin
   FEditSettings.Left   := 148;
   FEditSettings.Top    := 8;
   FEditSettings.Width  := 140;
-  FEditSettings.Text   := '115200,N,8,1';
+  FEditSettings.Text   := '9600,N,8,1';
 
   FBtnOpen := TButton.Create(Self);
   FBtnOpen.Parent  := Self;
@@ -174,15 +164,6 @@ begin
   FAnsi.Left      := 0;
   FAnsi.Top       := 38;
   FAnsi.OnKeyData := AnsiKeyData;
-
-  { Font diagnostic: write known CP437 box-drawing characters.         }
-  { If the OEM font is working, you should see:                        }
-  {   Line 1: single-line box top    ┌───┐                             }
-  {   Line 2: shade + full block     ░▒▓█                              }
-  {   Line 3: single-line box bottom └───┘                             }
-  { If you see accented letters (Ú Ä ¿ ° ± ² Û À Ù), the font is     }
-  { ANSI_CHARSET instead of OEM_CHARSET.                               }
-  FAnsi.Write(#$DA#$C4#$C4#$C4#$BF' '#$B0#$B1#$B2#$DB' '#$C0#$C4#$C4#$C4#$D9#13#10);
 end;
 
 

drv/commdrv.c

@@ -259,13 +259,6 @@ void applyBaudRate(PortStateT *port, uint16_t baud)
     base    = port->baseAddr;
     divisor = (uint16_t)(BAUD_DIVISOR_BASE / actualBaud);
 
-    // Guard: divisor 0 means the UART treats it as 65536, giving ~1.76 baud.
-    // This can happen when BuildCommDCB stores a raw truncated value for
-    // 115200 (e.g. 0xE101 = 57601) and a future rate exceeds 115200.
-    if (divisor == 0) {
-        divisor = 1;
-    }
-
     // Set DLAB to access divisor latch
     lcr = (uint8_t)_inp(base + UART_LCR);
     _outp(base + UART_LCR, lcr | LCR_DLAB);
@@ -322,11 +315,6 @@ void applyLineParams(PortStateT *port, uint8_t byteSize, uint8_t parity, uint8_t
             break;
     }
 
-    dbgHex16("KPCOMM: applyLine byteSize", (uint16_t)byteSize);
-    dbgHex16("KPCOMM: applyLine parity", (uint16_t)parity);
-    dbgHex16("KPCOMM: applyLine stopBits", (uint16_t)stopBits);
-    dbgHex16("KPCOMM: applyLine LCR", (uint16_t)lcr);
-
     _outp(base + UART_LCR, lcr);
 
     port->byteSize = byteSize;
@@ -960,12 +948,10 @@ int16_t FAR PASCAL _export inicom(DCB FAR *dcb)
     _inp(port->baseAddr + UART_RBR);
 
     // Populate ComDEB for third-party compatibility
-    port->comDeb.port       = port->baseAddr;
+    port->comDeb.port      = port->baseAddr;
     port->comDeb.baudRate   = port->baudRate;
     port->comDeb.qInSize    = port->rxSize;
     port->comDeb.qOutSize   = port->txSize;
-    port->comDeb.lcrShadow  = (uint8_t)_inp(port->baseAddr + UART_LCR);
-    port->comDeb.mcrShadow  = (uint8_t)_inp(port->baseAddr + UART_MCR);
 
     // Enable receive and line status interrupts
     _outp(port->baseAddr + UART_IER, IER_RDA | IER_LSI | IER_MSI);
@@ -1115,9 +1101,7 @@ void primeTx(PortStateT *port)
 // reactivateOpenCommPorts - Reactivate all ports after task switch (ordinal 18)
 //
 // Called by Windows when switching back to this VM.
-// Restores full UART state: baud rate, line params (LCR), MCR, FIFOs,
-// and re-enables interrupts.  A DOS fullscreen app or VM switch may
-// have reprogrammed the UART, so we must restore everything.
+// Re-enables interrupts and restores MCR state.
 // -----------------------------------------------------------------------
 void FAR PASCAL _export reactivateOpenCommPorts(void)
 {
@@ -1133,12 +1117,6 @@ void FAR PASCAL _export reactivateOpenCommPorts(void)
             continue;
         }
 
-        // Restore baud rate (sets DLAB, writes divisor, clears DLAB)
-        applyBaudRate(port, port->baudRate);
-
-        // Restore line parameters (word length, parity, stop bits)
-        applyLineParams(port, port->byteSize, port->parity, port->stopBits);
-
         // Restore MCR (DTR, RTS, OUT2)
         mcr = MCR_OUT2;
         if (port->dtrState) {