Thread: accessing more than 64k of video memory

  1. #1
    Registered User
    Join Date
    Sep 2001

    accessing more than 64k of video memory

    In c++ class we use dos (no dpmi) borland compilers and use bgi stuff if we need to do graphics. But there is this graphics library that some kid made a while back that the teacher let me use. The graphics library can do **** like 640x480x256 and 1024x768x256. Im assuming the kid wrote it in asm but How did he access that much video memory. All I can access is 64k. Any ideas how he did this?


  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    The edge of the known universe
    It's called bank switching - you set up your 64K window to overlay some part of a larger area of video memory.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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