As we know that VB can’t program to connect through
So now, we will introduce creating DLL file (Dynamic LInk LIbrary) by Borland Delphi, using Assembly programming to help for connecting through port by using the function of Assembly.
|
IN AL,DX |
Get value at port’s position according to value in DX that is kept at |
|
OUT |
Send value in |
push dx
mov dx,AddressPort ; AddressPort variable that get value from calling function
mov al,ValueByte ; ValueByte variable that get value from calling function
out dx,al
pop dx
- In the part of INPUT is the function of Assembly, reading value from input port that has value of port at 0 - 65,535 that will be used in
push dx
mov dx,AddressPort ; AddressPort variable that get value from calling function.
in al,dx
mov ValueByte,al ; ValueByte variable that send value back when call function.
pop dx
So now, we begin in the part of Delphi. Start opening New file in Pascal. We will not mention the other details, we will show just Code that is the function only, then copy to put on code in Delphi that in the part of output per is programmed as Procedure. For input, using programming as Function.
Library InOutVB; { set library name}
Uses SysUtils;
{procedure for sending value at port}
Procedure
OutVB(AddressPort:smallint ; ValUse:smallint);stdcall;export
Var
ValueByte:Byte;
Begin
ValurByte:=Byte(ValUse);
{ type asm function in order to be the part of program that is written by Assembly }
asm
push dx
mov dx,AddressPort
mov al,ValueByte
out dx,al
pop dx
End;
End ;
Function InVB(AddressPort:smallint):smallint;stdcall;export;
Var
ValueByte:Byte;
Begin
asm
push dx
mov dx,AddressPort
in al,dx
mov ValueByte,al
pop dx
End;
InVB:=smallint(ValueByte) and $00FF; { feedback to the function.
End
Exports
InWin ;
OutWin ;
Begin
End
We can comply program as DLL file, for convenience, you can copy code in TextBox below.
When we begin to use in VIsaul BasIc program, we have to declare the function in module (.BAS) that has the form like this,
Declare Function InVB LIB “InOutVB” (Byval port As Integer) As Long
Declare Function OutVB LIB “InOutVB” (Byval port As Integer, Byval bytedata As Long) As Long
For example, using the function to program connecting Printer port in Visual Basic
Label1.Caption=InVB(&H378) ‘ get value from Printer port.
OutVB (&H378,H&08) ’send value to Printer port.
All are the fundamental that can be used to program by Delphi in other types. After using the ready-made function is port in Pascal. Now, we try to program as Assembly for using.
[…] connect port. In this article, I will present programming by C++ first. For someone who likes to program by Borland Delphi, click here. Let’s begin program DII file by MS VC++6 by using function connect with Input and Output of port […]