Set RTS with Delphi4 console app

[Pirsig]

Hello.

I am trying to write a very simple Delphi4 32-bit console app which toggles the RTS pin of the COM1 RS232 serial port.

What is the simplest way to do this?

I tried writing asm code (see below) but not surprisingly I got a run-time exception:

Exception EPrivilege in module z.exe at 00008254. Privileged instruction.

Does Delphi4 have built-in support for toggling RTS? I could not find it.

Thank you.

procedure SetRTS;
asm  
mov dx, 03fch;   {get COM1 MCR}
in al,dx;
or al, 2;        {set RTS}
out dx, al; 
end;  

procedure ClearRTS;
asm  
mov dx, 03fch;
in al,dx;
and al, 0fdh;
out dx, al; 
end;

[pritaeas]

This may help: http://mc-computing.com/languages/delphi/delphi_serialio.htm

[Pirsig]

This may help: http://mc-computing.com/languages/delphi/delphi_serialio.htm

Thanks for the reference. There was no mention in there how to access the modem control register to toggle RTS... but there were quite a few external links; I haven't yet looked at them all but I will.