DOS ain't dead

Protectmode handler called from realmode (Developers)

posted by ecm  , Düsseldorf, Germany, 12.08.2010, 21:24

> add word ptr es:[edi+2Eh],4 {or "6"?}     {sets SP}

Did you try 6 already? Should be right. Also, you should restore the flags too.

> Set_rm_interrupt($13,new13h);
> {restores normal state}

Needs to use old13h.

With your current code, it might be a problem that other Int13 calls will get to your handler too. Instead of simulating an iret, you should chain to the old RM Int13 handler. (Simply set cs and ip appropriately, instead of from the stack.)

---
l

Complete thread:

• Protectmode handler called from realmode - Laaca, 12.08.2010, 21:12 (Developers)
  • Protectmode handler called from realmode - ecm, 12.08.2010, 21:24
    • Protectmode handler called from realmode - Laaca, 13.08.2010, 01:46
      • Protectmode handler called from realmode - Japheth, 13.08.2010, 07:31
        • Protectmode handler called from realmode - bretjohn, 13.08.2010, 18:43
          • EDIT: Protectmode handler called from realmode - bretjohn, 13.08.2010, 19:25
            • Volumes vs physical storage media | WAS "Protectmod handl" - DOS386, 26.08.2010, 09:33
              • Volumes vs physical storage media | WAS "Protectmod handl" - bretjohn, 26.08.2010, 19:03
                • Volumes vs physical storage media | WAS "Protectmod handl" - DOS386, 27.08.2010, 03:25
                  • Volumes vs physical storage media | WAS "Protectmod handl" - bretjohn, 27.08.2010, 16:47
                    • Volumes vs physical storage media | WAS "Protectmod handl" - DOS386, 28.08.2010, 01:26
                      • Volumes vs physical storage media | WAS "Protectmod handl" - bretjohn, 28.08.2010, 16:35
                        • Volumes vs physical storage media | WAS "Protectmod handl" - DOS386, 06.09.2010, 20:10