[Bug 6361] New: inb, outb (and probably others) crash wine

[Wine Bugs]

http://bugs.winehq.org/show_bug.cgi?id=6361

Summary: inb, outb (and probably others) crash wine
           Product: Wine
           Version: CVS
          Platform: PC
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: wine-dos
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

I have a DOS/VM86 application that attempts to directly use the serial port's
I/O registers. Wine gets an unhandled page fault error. The fault appears to
happen on a pop %es instruction in the code winebuild adds to the dlls after the
call. It seems that that the pop %es is getting sent off into the VM86
INSTR_EmulateInstruction routine.

The failure is completely reproducible. I put together a small .exe to reproduce
the problem that simply does a few outb calls and attempts to read data via inb.
It fails on the first outb.

I have stared at this long enough to realize there is something I am missing on
how VM86 mode works how to interpret the debugging output.

Any help on aiming me in the "right" direction would be appreciated.