🚀 go-pugleaf

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?

Tschuess,
David Paschal