Brokenthorn's Known Bugs: Difference between revisions
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Brokenthorn's tutorials are some of the better OSDev tutorials out there. They teach better coding practices, and go very in depth. Like all tutorials, there are a few bugs in it. Here are the most prevalent: |
[[Category:FAQ]]Brokenthorn's tutorials are some of the better OSDev tutorials out there. They teach better coding practices, and go very in depth. Like all tutorials, there are a few bugs in it. Here are the most prevalent: |
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==Wrong description of CR0.PE== |
==Wrong description of CR0.PE== |
Latest revision as of 22:05, 1 September 2020
Brokenthorn's tutorials are some of the better OSDev tutorials out there. They teach better coding practices, and go very in depth. Like all tutorials, there are a few bugs in it. Here are the most prevalent:
Wrong description of CR0.PE
In OSDev8, CR0.PE (bit 0) is incorrectly described as setting the processor to 32-bit mode. Setting bit 0 of CR0 does not put the processor in 32-bit mode. Performing a far jump to a 32-bit code segment puts the processor in 32-bit mode. The far jump itself will still be executed in 16-bit mode.
iret using inline ASM
In OSDev15, the provided ISR handler uses inline asm to iretd from a C function:
void int_handler_5 () {
_asm add esp, 12
_asm pushad
// do whatever...
_asm popad
_asm iretd
}
This makes assumptions about the calling conventions used, and isn't a good idea in general. Better options may be found here.
Missing semicolon
In OSDevPE, there is a missing semicolon in the IMAGE_THUNK_DATA structure
Issues with paging code
In OSDev18, the paging code has some issues. It directly accesses physical memory without mapping it. You can use it as a base, but implement recursive paging.