Mail Archives: djgpp/1998/02/13/01:42:49
At 01:40 2/13/1998 GMT, Sahaja wrote:
>Hi guys,
>
>could any body tell me what djgpp is?
Basically, it's a development system for writing 32-bit protected-mode
programs for DOS. For a more complete answer get the FAQ.
(ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2/faq210b.zip)
> I am planning to write a protected
>mode application; I saw some body mentioning about cwsdpmi or somthing;
>where can i get it from? I planning to run my application in plain dos!
CWSDPMI is a free DPMI host. It provides the DPMI services that DJGPP uses
to use protected mode. It's in the v2misc directory of the djgpp tree on
simtelnet.
If you use DJGPP to write your program, it will be much easier. All the
complicated DPMI stuff is done for you; you just write your C code and enjoy
the benefits!
Nate Eldredge
eldredge AT ap DOT net
devices be mapped into physical
memory, or will the software be using DMA techniques to access them? If the
former, yes, you can do that with DPMI services. See the function
`__djgpp_map_physical_memory' in the libc docs. Note that you must use
CWSDPMI or another DPMI 1.0 server. Windows will not work.
If the latter, I don't know. :\
I don't think you can use DPMI services like that without writing a
protected mode program, and DJGPP is the best way to do that, IMHO.
>
>Is there any additional convenience i get by using the dos extender except
>that it permits our application to stay in extended memory (which is not
>very important to me, as i am not expecting my code be more than
>640kbytes)?
You will also get protection from various bugs like NULL dereferences and
pointer overruns.
Incidentally, DJGPP does not use a DOS extender, only standard DPMI functions.
Nate Eldredge
eldredge AT ap DOT net
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