Whenever i try to switch over to pmode in bootloader
PC simply restsrts .
Anyone there to help me ?
bye
PC rebooting in pmode
- Pype.Clicker
- Member

- Posts: 5964
- Joined: Wed Oct 18, 2006 2:31 am
- Location: In a galaxy, far, far away
- Contact:
Re:PC rebooting in pmode
basically, the 386+ cpu will reboot automatically if a "tripple fault" condition is encountered.
In other words, when something got wrong in pmode, you get an exception (page fault, general protection fault, division error, etc.). The cpu uses the interrupts mechansim to report the fault/error, but if it even fails to deliver the interrupt (for instance because your interrupt table is on a missing page), it will raise a "double fault" exception.
If another exception occurs while the CPU is trying to call the "double fault" exception handler, you're in tripple fault" condition, and the CPU resets.
Imho, the best way for you to locate your problem is to run your OS in a virtual PC like bochs which should be able to give you additionnal information like the register contents at the exception, or the 'name' of the initial exception.
In other words, when something got wrong in pmode, you get an exception (page fault, general protection fault, division error, etc.). The cpu uses the interrupts mechansim to report the fault/error, but if it even fails to deliver the interrupt (for instance because your interrupt table is on a missing page), it will raise a "double fault" exception.
If another exception occurs while the CPU is trying to call the "double fault" exception handler, you're in tripple fault" condition, and the CPU resets.
Imho, the best way for you to locate your problem is to run your OS in a virtual PC like bochs which should be able to give you additionnal information like the register contents at the exception, or the 'name' of the initial exception.