From: Corelli Marco <mcorelli AT gtwparc DOT padova DOT ccr DOT it>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Accesing from 0xFFFF:F000 to 0xFFFF:FFFF physical memory address
Date: Fri, 13 Oct 2000 17:18:07 +0200
Organization: IUnet
Lines: 29
Message-ID: <39E727AF.93D0FFD3@gtwparc.padova.ccr.it>
References: <39E5E00A DOT 39A80E46 AT gtwparc DOT padova DOT ccr DOT it> <7263-Thu12Oct2000193356+0300-eliz AT is DOT elta DOT co DOT il> <39E6C1EB DOT 58AED5F3 AT gtwparc DOT padova DOT ccr DOT it> <8011-Fri13Oct2000132503+0300-eliz AT is DOT elta DOT co DOT il> <39E70A59 DOT 1ABE9F69 AT gtwparc DOT padova DOT ccr DOT it> <6480-Fri13Oct2000170135+0300-eliz AT is DOT elta DOT co DOT il>
NNTP-Posting-Host: proxy.iperv.it
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Trace: serv1.iunet.it 971449974 20352 151.4.122.158 (13 Oct 2000 15:12:54 GMT)
X-Complaints-To: newsmaster AT iunet DOT it
NNTP-Posting-Date: 13 Oct 2000 15:12:54 GMT
X-Mailer: Mozilla 4.75 [en] (Win98; U)
X-Accept-Language: en
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com



> Didn't you say in your original message that the address you wanted to
> map was at FFFC:0000 to FFFF:FFFF?  Are those real-mode segment:offset
> addresses, or did you mean to say FFFC0000, a 32-bit physical address?
> There's a big difference between these two alternatives.

It's a physical address from FFFC000 to FFFFFFFF!!

> The above setup of the FS register is correct for 32-bit physical
> address FFFC0000, but incorrect for FFFC:0000.
>
> > byte_read = _farpeekb ( selector, i ) ;

> Please tell what is the first value of i for which the program
> crashes.

It's crash at first value : zero!!!

> >         __dpmi_physical_address_mapping( &mem ) ;
> >         selector = __dpmi_allocate_ldt_descriptors ( 1 ) ;
> >         __dpmi_set_segment_base_address ( selector, mem.address ) ;
> >         __dpmi_set_segment_limit ( selector, mem.size - 1 ) ;
>
> Did all those functions succeed, or did some of them returned -1?

All function succeed!!! I test the result an it't != -1 !!!!