🚀 go-pugleaf

In article <1992Sep1.143350.10587@ncsu.edu> dspascha@eos.ncsu.edu (DAVID SCOTT PASCHAL) writes:
>
>Hi.  The 386 and better can be set up to generate a general protection fault
>when a process does an IN or OUT to a specific I/O port based on an I/O
>permission bitmap in the Task State Segment, but this only works in protected
>mode where there are TSS's, not in real mode in which MS-DOS operates.  I
>guess you could write a little (not!) DOS extender that runs DOS in V86 mode
>(which is really a real mode process running within protected mode which is how
>Windows multitasks DOS applications in 386-Enhanced mode), but this would be
>extremely difficult to design properly to handle BIOS interrupts and DMA.
>
>Simulating interrupts would be pretty easy to do in real mode -- in your
>"custom" interrupt handler, just call any interrupt handler you want.
>
>Since this is your "own custom hardware", why don't you just simulate these I/O
>ports in your adapter?

   I would like to find a software only solution if possible.
   The software that needs to do the IO trapping will be put into
   existing 386 machines and we would like to avoid modifying
   them by adding cards etc. 
>
>Tschuess,
>David Paschal


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