Re: access PCI memory from DOS

[Ivor Bowden <ivor@peritek.com>]

I don't know how to write a device driver,
but I access PCI memory from DOS a lot,
it is pretty easy.

I use the djgpp DOS port of the gnu C compiler
http://www.delorie.com/djgpp/

I use the int86(0x1a) routines for getting the
PCI addresses, setting config registers, etc. and
__dpmi_physical_address_mapping
__dpmi_allocate_ldt_descriptors
__dpmi_set_segment_base_address
__dpmi_set_segment_limit
for getting memory selectors
and
the _farpeek and _farpoke routiens
for memory access.

You need to have a DPMI server. I think that is already
on a W98 system, but for DOS you can use cwsdpmi.exe,
freely available. This method does not work on an NT system.

Let me know if you have any more questions.

-Ivor

At 10:08 AM 7/3/01 +0200, you wrote:
>	Dear, 
>	
>	As we are a member of PCI-SIG, i think this is the best place to
>post my 
>	question : 
>	We have made a pci card that has an on board 128kb memory. I wrote a
>windows 
>	device driver to access the memory, and this works perfect. 
>	
>	We now want to write a "DOS driver", so that we can access the
>memory in 
>	plain DOS. 
>	
>	- Is this possible 
>	- Are there any C source codes available. 
>	
>	I would appreciate any help! 
>	
>	Thanks in advance, 
>	
>	JOHan Hallez 
>	Sycron NV 
>	Tel +32 50 833 333 
>	Fax +32 50 833 399
>
>
>