DOS ain't dead

not setting carry (Developers)

posted by ecm  , Düsseldorf, Germany, 17.10.2025, 11:31

> > That means all calls above ah=6Ch are high.
>
> Thanks for all that effort to determine what was happening.
>
> I have documented that here:
>
> https://sourceforge.net/p/pdos/gitcode/ci/8274f934426a4cb78b86a92fc6fac30a07f58ef5/

Addendum: MS-DOS v7.00 sets ax = 7100h and CY (set Carry Flag) on eg function 716Ch when running without the MSW v4 part. So that may be part of the reason it isn't well documented that you should stc for older MS-DOS.

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Complete thread:

• not setting carry - kerravon, 16.10.2025, 10:29
  • not setting carry - ecm, 16.10.2025, 16:17
    • not setting carry - bretjohn, 16.10.2025, 23:59
      • not setting carry - ecm, 17.10.2025, 09:30
    • not setting carry - kerravon, 17.10.2025, 07:58
      • not setting carry - ecm, 17.10.2025, 10:29
        • not setting carry - kerravon, 17.10.2025, 10:55
          • not setting carry - ecm, 17.10.2025, 11:31
            • not setting carry - kerravon, 17.10.2025, 16:51
              • not setting carry - ecm, 17.10.2025, 18:43
                • not setting carry - kerravon, 17.10.2025, 19:05