From: "Dark Angel" <mop45440 AT mail DOT telepac DOT pt>
Newsgroups: comp.os.msdos.djgpp
Subject: SELECTORS PROBLEM!!
Date: 12 May 1998 19:57:34 GMT
Organization: Dark Angel Soft
Lines: 27
Message-ID: <01bd7dd7$7088dc20$LocalHost@default>
NNTP-Posting-Host: 194.65.253.202
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk


I have writen an assembly function that puts a pixel on the screen in SVGA
640x480.
It works. But it shouldn't, i think...

I get the selector for the 0xa000 address with the function:

	 _dmpi_segment_to_descriptor(0xa000)

then i have transcribed the _farpokeptr asm code from the header file into
my asm
function, no problem.


But shoudn't the selector returned by _dpmi_segment_to_descriptor give me
only access to the first 64k of the video memory (first video page: 64k * 4
banks) ?

I was expecting some sort of memory write error when i tried to write way
past the first page. But the function still worked!


Is it true that the selector returned by the dpmi function gives me only
access to 64k or not?! If not, do i have free access to all the VRam using
that selector?