GNAT: WIN95 - System.Address Question...

GNAT: WIN95 - System.Address Question...

[Mike Gardner]

Hello,

I'm writing an interface to an EISA card which sits in a Gateway
computer running WIN95.  I need to write a 0x0001 to a real-mode address
of CC00H:0804H.  Since WIN95 is running in protected-mode, I assume that
I need to buy/write a package for peeking and poking values to real-mode
addresses...  My question is this...  Will the GNAT for WIN95 system
allow me to directly write to a real-mode address and it handles the
nasties of the protected-mode interface?  My hunch is that I cannot just
simply use the System.Address stuff on this platform and must buy/write
an interface package to give me a porthole from protected-mode to
real-mode.  What do you think?

Thanks in advance!

Mike Gardner
mike.gardner@ab.com

Re: GNAT: WIN95 - System.Address Question...

[David C. Hoos, Sr.]

Mike Gardner <mike.gardner@ab.com> wrote in article
<3240134A.7877@ab.com>...
> Hello,
> 
> I'm writing an interface to an EISA card which sits in a Gateway
> computer running WIN95.  I need to write a 0x0001 to a real-mode address
> of CC00H:0804H.  Since WIN95 is running in protected-mode, I assume that
> I need to buy/write a package for peeking and poking values to real-mode
> addresses...  My question is this...  Will the GNAT for WIN95 system
> allow me to directly write to a real-mode address and it handles the
> nasties of the protected-mode interface?  My hunch is that I cannot just
> simply use the System.Address stuff on this platform and must buy/write
> an interface package to give me a porthole from protected-mode to
> real-mode.  What do you think?
> 
> Thanks in advance!
> 
> Mike Gardner
> mike.gardner@ab.com
> 
Hi Mike,
You're right that you can't use System.Address.  System.Address values are
addresses in the virtual address space of your program -- i.e. 32-bit
values which know nothing about segment:offset types of addresses.
What you need is the Win32 DDK (Device Driver Kit).  Then you can use the
Interfaces.C stuff, and Pragma interface to get to the routines you need. 
I've wanted to do enough of that to get "hands on" experience with it, but
just haven't had the time.
Hope this helps
-- 
David C. Hoos, Sr.,
http://www.dbhwww.com
http://www.ada95.com

Re: GNAT: WIN95 - System.Address Question...

[Tom Griest]

In article <3240134A.7877@ab.com> mike.gardner@ab.com writes:

>I'm writing an interface to an EISA card which sits in a Gateway
>computer running WIN95.  I need to write a 0x0001 to a real-mode address
>of CC00H:0804H.  Since WIN95 is running in protected-mode, I assume that
>I need to buy/write a package for peeking and poking values to real-mode
>addresses...  My question is this...  Will the GNAT for WIN95 system
>allow me to directly write to a real-mode address and it handles the
>nasties of the protected-mode interface?  My hunch is that I cannot just
>simply use the System.Address stuff on this platform and must buy/write
>an interface package to give me a porthole from protected-mode to
>real-mode.  What do you think?

I think you should write a device driver.  This is the proper "model" to
follow when interfacing with hardware.  Probably the best way is to
get the MS Device Driver Kit (DDK).  I believe some companies sell
something like what you want "a porthole", but I can't recall their
names.  There may also be some sample drivers on the net (I know there
are many samples in the DDK).

-Tom