Date: Sat, 02 Jun 2001 08:52:48 +0300
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
Sender: halo1 AT zahav DOT net DOT il
To: yurick AT oblik DOT dp DOT ua
Message-Id: <2110-Sat02Jun2001085247+0300-eliz@is.elta.co.il>
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CC: djgpp AT delorie DOT com
In-reply-to: <jtb8f9.4ql.ln@nix-if1> (yurick@oblik.dp.ua)
Subject: Re: __djgpp_map_physical_memory - some questions
References: <r6e3f9 DOT tu3 DOT ln AT nix-if1> <7458-Thu31May2001062819+0300-eliz AT is DOT elta DOT co DOT il> <jtb8f9 DOT 4ql DOT ln AT nix-if1>
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> From: yurick AT oblik DOT dp DOT ua
> Newsgroups: comp.os.msdos.djgpp
> Date: Fri, 1 Jun 2001 18:21:23 +0300
> 
> Thu, 31 May 2001 06:28:19 +0300, Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:
> 
> >> 2. I've tried this with djgpp 2.03 under Win95OSR2. Is it supports
> >> this call (DPMI 0508)?
> EZ> The docs clearly says that this is DPMI 1.0 function, and that most
> EZ> DPMI hosts don't support it.  Windows doesn't.
>    I has been read docs but I hoped against hope :)

Abandon hope, anyone who uses Windows ;-)

>    Well, what can I do with it? Can I use _farpoke*() with _dos_ds 
> for this? I need to access physical address 0xeb000000 (which is not 
> in 1st meg of course). And will DPMI host allows such access or I must
> make some other calls for this?

What is at that address?  If it's some memory-mapped device, you
should be able to use the method described in section 18.7 of the
FAQ.

> 	And if _farpoke*() is answer, I can't understand, how this works? 
> I hasn't allocated memory at this address so DPMI host must blame me, 
> hasn't it?

Without mapping that address into some segment for which there's a
valid descriptor, you will indeed get a Page Fault.  _farpeek* and
_farpoke* only work for valid selectors.  One of the things the code
presented in section 18.7 of the FAQ does is indeed create a
descriptor for the memory you are mapping in.