DOS ain't dead

DPMI - how to chain user and original RM handler? (Developers)

posted by ecm  , Düsseldorf, Germany, 29.04.2023, 08:45

> > call es:[oldint15_handler] {DOES NOT WORK !!! (Crashes here)}
> > {oldint15_handler is got from Get_rm_interrupt($15, oldint15_handler)}
>
> You need to far call the downlink in Real/Virtual 86 Mode, not in PM. And
> you need a pushfw instruction before the far call.
>
> > mov eax,ds:[esi+0] {restore return address
> > (CS:IP)}
> > mov es:[edi+2Ah],eax

You can probably get away with loading the dword from oldint15_handler and store it in [es:edi + 2Ah], then do not change the stack pointer.

---
l

Complete thread:

• DPMI - how to chain user and original RM handler? - Laaca, 29.04.2023, 00:41 (Developers)
  • DPMI - how to chain user and original RM handler? - ecm, 29.04.2023, 08:43
    • DPMI - how to chain user and original RM handler? - ecm, 29.04.2023, 08:45
      • DPMI - how to chain user and original RM handler? - Laaca, 29.04.2023, 14:04
        • DPMI - how to chain user and original RM handler? - ecm, 29.04.2023, 15:17
  • DPMI - how to chain user and original RM handler? - bretjohn, 04.05.2023, 04:03
  • DPMI - how to chain user and original RM handler? - CandyMan, 05.05.2023, 12:36
    • DPMI - how to chain user and original RM handler? - Laaca, 05.05.2023, 21:53
    • DPMI - how to chain user and original RM handler? - Laaca, 12.06.2023, 23:39