X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f
NNTP-Posting-Date: Thu, 25 Jul 2013 18:56:30 -0500
From: "Charles Sandmann" <cwsdpmi AT earthlink DOT net>
Newsgroups: comp.os.msdos.djgpp
References: <rNWdnSFu4b2QMtfWnZ2dnUVZ_tmdnZ2d AT earthlink DOT com> <09068ed9-d989-4db5-bc71-2eabcbf1db53 AT googlegroups DOT com>
Subject: Re: Beta Test:  CWSDPMI r7 - 4GB support
Date: Thu, 25 Jul 2013 18:56:26 -0500
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2900.5931
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157
X-RFC2646: Format=Flowed; Original
Message-ID: <t5OdnS4B7e2zJmzMnZ2dnUVZ_oGdnZ2d@earthlink.com>
Lines: 27
X-Usenet-Provider: http://www.giganews.com
NNTP-Posting-Host: 64.91.136.221
X-Trace: sv3-XlsIou/RiyMewSVTArmZotKLxdsKLOUOTPYaFhV5iphBPjlmfJzs9p/o9Gtpzoa+8hPEcf0uwatgYqW!v+PCjBhQAKpZ4qlm78OlA9CkL1KUJ1ZM4lIzdwRk7Ds1AWVVNtMdbvdwsIZ0eWzTF5BgzwXlhkXy!wLzj3W3MIFXWM3TjkEUIB+33Ga4MtaLS
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
Bytes: 2355
X-Original-Bytes: 2294
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

<jimmyliaoo AT gmail DOT com> wrote in message 
news:09068ed9-d989-4db5-bc71-2eabcbf1db53 AT googlegroups DOT com...
> I have one question about CWSDPMI r7 for 5GB+ support...
>
> "...For those who need more than 4GB, I'll provide some code that allows 
> you
> to map 5GB+ memory (up to 64GB) into the address space on request"
>
> => Does this means(for example) if I allocate memory buffer then the 
> returned pointer will point to the physical
>memory "beyond 4GB" ? Am I correct ?    Ex. the pointer value is 
>0x100000000 ....

CWSDPMI uses the page tables to re-map your system memory, making the first 
4GB appear to be (mostly)
memory, filling the memory holes, replacing video ram, etc.  So usually some 
of the memory will come from above
the 4GB mark.  But all of your pointers are 32-bit due to the page table 
remapping.

If you want to access more then 4GB total, then a memory window is set up, 
which you then can point to the
remaining unused memory.  This is similar to EMS memory in the DOS 16-bit 
days, so it is up to the user to manage
which section of memory is available in the "window".