Trouble using INT's from Windows-program

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5 total messages Started by Indridi Bjornsson Thu, 09 Apr 1992 12:25

#252

Author: Indridi Bjornsson
Date: Thu, 09 Apr 1992 12:25

61 lines
2395 bytes

       Greatings fellow netters :)

   A friend of mine is writing some kind of communication
program in windows. The driver is called TES and is 
located at INT 14. The services TES provides are A0 through A8.
He is using Borland C++ 3.0. 

   Most of the services work, just by using int86x() inside
the program, but when he tries to send a string, TES doesn't
seem to get the right one, just some garbage. 

   The string is supposed to be pointed by DS:SI. I.e. to do a
connect:

-------------------------------------------------------------
   AH = A3h Connect a New Session with <NAME>

Call with:
   DS:SI points to a (null-terminated) string within the user 
   data space, naming a known server.

Returns with:
   AH = 0 if successful, and AL = session number activated, or
   AH = FF if unsuccessful, and AL = error code.
-------------------------------------------------------------
   
   So he though of doing something like:

void connect()
{
   union REGS regs;
   struct SREGS sregs;
   static char *Name = "Server";

   regs.x.ax = 0xA300;
   regs.x.dx = 0x00;
   regs.x.si = FP_OFF( Name );
   sregs.ds = FP_SEG( Name );

   int86x( INT, &regs, &regs, &sregs );
}


   But this doesn't seem to work, TES always get send some 
garbaged string. That is if an UAE doesn't creep up at his
display.


   So what is the catch here? It doesn't seem to matter wether 
he declares all segments FIXED or not?

Thanks,
Indridi.

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Re: Trouble using INT's from Windows-program

#280

Author: Steven Arthur Nelson
Date: Fri, 10 Apr 1992 01:24

18 lines
1068 bytes

>   A friend of mine is writing some kind of communication
>program in windows. The driver is called TES and is 
>located at INT 14. The services TES provides are A0 through A8.
>He is using Borland C++ 3.0. 

>   Most of the services work, just by using int86x() inside
>the program, but when he tries to send a string, TES doesn't
>seem to get the right one, just some garbage. 

>   The string is supposed to be pointed by DS:SI. I.e. to do a
>connect:

Tell your friend to try using DPMI service 0x300 to simulate a 
real mode interrupt.  All memory addresses passed between real
and protected modes should be allocated using GlobalDosAlloc.   

Steven Nelson

Re: Trouble using INT's from Windows-program

#376

Author: Richard Hancock
Date: Tue, 14 Apr 1992 16:27

8 lines
903 bytes

/ hpopd:comp.windows.ms.programmer / san@cup.portal.com (Steven Arthur Nelson) /  2:24 am  Apr 10, 1992 /

>Tell your friend to try using DPMI service 0x300 to simulate a 
>real mode interrupt.  All memory addresses passed between real
>and protected modes should be allocated using GlobalDosAlloc.

Isn't it sufficient to use GlobalDosAlloc? Surely Windows will
reflect the interrupt to real mode (via DPMI)?

Re: Trouble using INT's from Windows-program

#397

Author: Richard Hancock
Date: Wed, 15 Apr 1992 10:20

12 lines
1050 bytes

/ hpopd:comp.windows.ms.programmer / richardh@hpopd.pwd.hp.com (Richard Hancock) /  5:27 pm  Apr 14, 1992 /
/ hpopd:comp.windows.ms.programmer / san@cup.portal.com (Steven Arthur Nelson) /  2:24 am  Apr 10, 1992 /

>>Tell your friend to try using DPMI service 0x300 to simulate a 
>>real mode interrupt.  All memory addresses passed between real
>>and protected modes should be allocated using GlobalDosAlloc.
>
>Isn't it sufficient to use GlobalDosAlloc? Surely Windows will
>reflect the interrupt to real mode (via DPMI)?

Please ignore my stupidity - I'd forgotten the additional
complication of needing to pass a segment address in DS.

Re: Trouble using INT's from Windows-program

#436

Author: Jim Beveridge
Date: Wed, 15 Apr 1992 19:29

26 lines
1370 bytes

In article <4764@krafla.rhi.hi.is>, indridi@rhi.hi.is (Indridi Bjornsson) writes:
>    A friend of mine is writing some kind of communication
> program in windows. The driver is called TES and is 
> located at INT 14. The services TES provides are A0 through A8.
> He is using Borland C++ 3.0. 
> 
>    Most of the services work, just by using int86x() inside
> the program, but when he tries to send a string, TES doesn't
> seem to get the right one, just some garbage. 
> 

The problem is that the string is stored in extended memory,
which a real mode program (which int86x calls) is unable
to look at.  You have to have this string copied to an
area of memory that is located below 640k.

Windows does this automatically for you for interrupts that
it understands.  Obviously, it doesn't understand this
interrupt.

There are functions in the SDK for getting and using memory below
640k, I just don't remember them off the top of my head.

Hope this helps.

	Jim

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