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Mail Archives: djgpp/1997/08/05/17:20:01

From: eggbrains AT aol DOT com (Egg brains)
Newsgroups: comp.os.msdos.djgpp
Subject: Using __dpmi_set_discriptor (and/or) __dpmi_segment_to_discriptor
Date: 5 Aug 1997 19:07:11 GMT
Lines: 27
Message-ID: <19970805190700.PAA22510@ladder01.news.aol.com>
NNTP-Posting-Host: ladder01.news.aol.com
Organization: AOL http://www.aol.com
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

that was a long message title...

anyway, i got this code (not mine)...
it is supposed to access 64KB of text-mode video memory at `0xB800:0000',
(courtesy of Bill Currie)

  static char selectorData[8] = {
    0xff, 0xff, 0x00, 0x80,
    0x0b, 0xf3, 0x40, 0x00
  };
    int screenSelector = __dpmi_allocate_ldt_descriptors (1);
    if (__dpmi_set_descriptor (screenSelector, selectorData) < 0)
      abort ();
    return screenSelector;

i can't fugure out how to set up my own place... like A000:0000 w/ a 256k
limit...  yes, i looked it up in the help and every thing, but i can't see
what the #'s he uses in his code come out to be 64 and/or B800:0000... i
tried convertying them to decimal and binary...

i was thinking of using __dpmi_segment_to_descriptor but that "always
defines a 64KB limit by default" is there anyway i can change that limit?

Paul

Thank you for your help. :-)

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