Troubleshooting: Difference between revisions
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The first thing ever to do is to implement a reliable 'exception handler' which will tell you what went wrong. Under an emulator like [[Bochs]], the absence of such a handler will lead to a '3rd Exception without resolution' panic message (a.k.a [[Triple Fault]]), if the emulator is configured to do so... On bare hardware, it will simply reset your computer with a laconic 'bip'. |
The first thing ever to do is to implement a reliable 'exception handler' which will tell you what went wrong. Under an emulator like [[Bochs]], the absence of such a handler will lead to a '3rd Exception without resolution' panic message (a.k.a [[Triple Fault]]), if the emulator is configured to do so... On bare hardware, it will simply reset your computer with a laconic 'bip'. |
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Every time the CPU is unable to call some exception handler, it tries to execute the [[Double Fault]] exception handler. If it fails to call it either, a [[Triple Fault]] occurs. Also keep in mind that exceptions cannot be masked, so either your code is perfect or you need exception handlers. |
Every time the CPU is unable to call some exception handler, it tries to execute the [[Double Fault]] exception handler. If it fails to call it either, a [[Triple Fault]] occurs. Also keep in mind that exceptions cannot be masked, so either your code is perfect or you need exception handlers. Also keep in mind that when you run applications '''''their''''' code must be perfect without exception handlers, so it's a good idea to get them quite quickly. |
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It's quite convenient to have the exception handler showing what kind of exception occurred before anything 'hazardous' is attempted. Displaying, for instance, the (hexadecimal) exception number in a corner of the screen, can save you hours of debugging. :) |
It's quite convenient to have the exception handler showing what kind of exception occurred before anything 'hazardous' is attempted. Displaying, for instance, the (hexadecimal) exception number in a corner of the screen, can save you hours of debugging. :) |
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