3rd exception
Posted: Sat Dec 14, 2002 2:50 pm
Hi everybody. Sometimes bochs gives a tick sound and then gives an error message of 3rd exception thing... What does that mean? Any ideas? Thanx in advance...
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Re:3rd exception
Posted: Sat Dec 14, 2002 7:34 pm
That means tripple fault.
Re:3rd exception
Posted: Sat Dec 14, 2002 10:46 pm
Perhaps a bit more detail is called for, Tom. 
A 'triple fault' is what happens when three consecutive unhandled exceptions or interrupts occur. When this happens, the CPU assumes it is in an invalid state and resets itself.
IIUC, the most common cause of it is that when an interrupt occurs when there is no valid handler for it and a CPU exception is raised as a result, if there is no handler for this exception as well, it raises the same error again, with the result that this third error, for which there is still no handler, puts the CPU into a state of triple fault.
This is a very common problem in the early stages of p-mode design, if an interrupt occurs when there is no valid IDT.
Comments and corrections are welcome.
A 'triple fault' is what happens when three consecutive unhandled exceptions or interrupts occur. When this happens, the CPU assumes it is in an invalid state and resets itself.
IIUC, the most common cause of it is that when an interrupt occurs when there is no valid handler for it and a CPU exception is raised as a result, if there is no handler for this exception as well, it raises the same error again, with the result that this third error, for which there is still no handler, puts the CPU into a state of triple fault.
This is a very common problem in the early stages of p-mode design, if an interrupt occurs when there is no valid IDT.
Comments and corrections are welcome.
Re:3rd exception
Posted: Sun Dec 15, 2002 4:15 am
Thanx for the responses, I want to ask another question, I think I have a valid IDT and it seems to work alright for IRQ 2 and other callable interupts, so where might be the problem? Thanx in advance...