Bare metal: set up basic CPU exception handling, with IDT & TSS #640
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Amazing work, @tkchia! |
| ezlea .excep_msg,di # stack should be 16-byte aligned now | ||
| xor %eax,%eax # kprintf is variadic; remember to | ||
| # pass no. of vector regs. used (= 0) | ||
| call kprintf # print error message |
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Is this going to force a dependency on kprintf() into o/tiny/examples/life.com? If so, we might want to do a one-off error report.
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Hello @jart,
Is this going to force a dependency on kprintf() into o/tiny/examples/life.com?
Not yet. I am trying to arrange to link in the IDT logic only when the program is already linking in some sort of crash debugging (I am still not familiar with how Cosmopolitan's crash debugging capability works).
Thank you!
| mov %cs,%eax | ||
| stosw | ||
| mov %rdx,%rax | ||
| // ┌P:present |
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I love how you did the CP437 diagrams.
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Hello @jart,
Well, it did take me quite a while to realize that I had to reload the GDTR to make it point to virtual memory — so that, when (re)loading Thank you! |
When a CPU exception (e.g. protection fault, divide by zero) happens in bare metal mode, the program should now be able to catch the exception and dump some information on the exception to the serial console, if one ropes in (
STATIC_YOINK) the symbol_idt.I hope to get the exception handlers to dump information to the VGA screen as well. It seems I will need to modify
kprintfto do this. Once this is implemented, it should be easier to diagnose any program crashes that occur on bare metal.Thank you!