VBE:in real mode or in protected mode

Question about which tools to use, bugs, the best way to implement a function, etc should go here. Don't forget to see if your question is answered in the wiki first! When in doubt post here.
shindow
Member
Member
Posts: 26
Joined: Thu Feb 25, 2010 7:35 am

Re: VBE:in real mode or in protected mode

Post by shindow »

I jump to vm86 mode,but when i execute int 3(it gets the from the vector table as in real mode do),let's say 0xff57.if i am in real mode ,it is okay,i don't know why it will judge the GDT's limit.The pic is as follows:
Attachments
test.jpg
User avatar
Combuster
Member
Member
Posts: 9301
Joined: Wed Oct 18, 2006 3:45 am
Libera.chat IRC: [com]buster
Location: On the balcony, where I can actually keep 1½m distance
Contact:

Re: VBE:in real mode or in protected mode

Post by Combuster »

Virtual 8086 mode traps back to protected mode when provoked, so that emulation software may do what would otherwise be done on real hardware. Interrupts are one such example.

Even so, your IDT/TSS is broken because it wants to load protected mode segments that doesn't exist.

P.S. please do post the log in plaintext next time.
"Certainly avoid yourself. He is a newbie and might not realize it. You'll hate his code deeply a few years down the road." - Sortie
[ My OS ] [ VDisk/SFS ]
shindow
Member
Member
Posts: 26
Joined: Thu Feb 25, 2010 7:35 am

Re: VBE:in real mode or in protected mode

Post by shindow »

Thank u,Combuster
Combuster wrote:Virtual 8086 mode traps back to protected mode when provoked, so that emulation software may do what would otherwise be done on real hardware. Interrupts are one such example.
Do you meaning that(commonly),if interrupts or exeception happens it always jump to protect mode,so it will jugde the GDT's limit?
Combuster wrote: P.S. please do post the log in plaintext next time.
I am sorry for that,i cannot copy the text from the bochs.I will pay attention next time.

My problem is solved yesterday,i find that if you set CR4.VME bit,it seems that you can use int n like in real mode,it works.

Thank you for all again!
Post Reply