High number segments

My developing chess program is DOS based and would stand alone as a .COM program although I usually run it under a debugger.

I'm using the B800 segment for the screen and segments above are mysterious for me.

Are there any higher number segments available for data storage? (I know much if it is ROM.)


  • C000-C7FF is the 32KB video BIOS, C800-CBFF is the now gone XT HD BIOS (I don't know about CC00-CFFF but it and the obsolete XT HD BIOS might have RAM), D000-EFFF are adapter RAM/ROMs, and F000-FFFF is of course the PC BIOS. I think you should try messing with A20 and using the HMA because it's got 16 bytes less than 64KB of RAM, but be careful because sometimes COMMAND.COM uses it. Maybe you could switch to mode 13h and then mode 3 with AL bit7 set to not destroy the RAM. Then you might get 64000 bytes of extra RAM (pretty slow though).

  • Thanks.

    Parking movelists has to be faster than re-generating them (especially now I can send 32bits at once!)

    And to think that a chess program could run in 4K using the Z80......

  • Z80s kick a$$ [when there's no x86 around]!
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