IA32 VM86 Mode

[TheUbu]

I was hoping some could help me out here with VM86 mode on the IA32 platform. I have set up a 16BIT TSS with what I assume to be the propper EFLAGS which are 2 | 0x200 | 0x20000 - However when it does the int 13 so I can some work for VM86 (this int 13 is a task gate not int) all the values in the tss for the 16 bit task seem to have taken on 32 bit values.

I wrote this referencing the intel developer manual if someone knows other references it would be much appreciated.


Christopher

[ASHLEY4]

Try here:

http://alexfru.chat.ru/epm.html#v86monitor

ASHLEY4.

[TheUbu]

That URL is not working....Anyone else?



Christopher

[ASHLEY4]

The person behind your pc is not working,as it works in my browser .

ASHLEY4.

[TheUbu]

No I keep getting connection timed out...



Christopher

[Gandalf]

hi friend,

I believe your quest will end with this site. This gives you all the info you need about VM86 (Believe me I made my own vm86 monitor from this tutorial and it is working great - I have tested a few bios functions with it).

http://www.openbg.net/sto/os/xml/v86.html

rgds
Gandalf

[TheUbu]

Thanks,

This site should help quite a bit... I had v86 working in the older version of my kernel but its apparently not functioning anymore so I needed a bit of a refresher.



Christopher

[TheUbu]

Not sure if anyone has seen anything like this.

I set up a new TSS with eflags for IOPL3 and vm bit set when i jump the tss it does an int 10 which causes a GPF the VM handler this is a task gate so the old TSS should be saved as the new one is started however when i print the values in the tss of the v86 task they are completly wrong for example the CS register is now 0x8 the gdt entry for ring 0 cs


Christopher