IPC@CHIP Documentation - SC12 @CHIP-RTOS V1.10

The interrupt declaration will motivate the compiler to emit code that sets the CPU's DS data segment register on
entry to the procedure, thus allowing access to the Pascal program's data.
The IPC@CHIP Web server handles the call to a Pascal CGI function differently than it does the call to a C
language CGI function. One input parameter is needed by all CGI functions, C or Pascal. This one parameter
is a far pointer to a rpCgi type structure (or in Pascal, a record). When calling a C language CGI function this
pointer is pushed onto the stack using a normal parameter passing mechanism. For Pascal CGI functions this
pointer is instead passed in the CPU's ES:DI registers. Consequently this pointer must be recovered by the
Pascal program. This can be done as follows:
procedure CgiMini_Proc;interrupt;
var
ESreg : Integer;
DIreg : Integer;
CGIRequest : rpCGIptr;
begin
asm
mov ax,es
mov Esreg,ax
mov ax,di
mov DIreg,ax
end;
CGIRequest := ptr(ESreg,DIreg);
............
end;
Installing a Pascal CGI procedure:
Pascal CGI procedure must be installed at the start of the DOS program with the CGI_INSTALL_PAS API call.
(CGI functions written in C must still be installed with the standard CGI_INSTALL API.)
For better understanding of programming CGI with Turbo Pascal, we provide some example programs compiled
with Borland Pascal 7.0.
1. cgiMini.exe
The CGI function installed by this program produces a HTML page which contains some of the request
parameters.
Examples for browser inputs:
http://192.168.205.4/cgimini
http://192.168.205.4/cgimini?Argument
2. countcgi.exe
We build a dynamic HTML page which contains the current value of a counter incremented in the main
loop of the program.
Browser input: http://192.168.205.4/countcgi
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