Strange behaviour, fetch_raw_descriptor

[mangaluve]

My OS behaves really weird some times. For instance, I just wrote a function (as a helper to printf) to print hex numbers. When I added the following line

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unsigned char test = 5;

in my code, the OS crashes when I runit in bochs. I got something like
Event type: PANIC
Dvice: [CPU ]
Message: fetch_raw_descriptor: LDTR.valid=0
what can this be?

[mangaluve]

What is the LDTR, I never use that as far as I know?
Well I have the following code

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void read_hdd_blocks(u8int count, u8int sector, u16int cylinder, u8int *buffer);
void read_hdd_blocks(u8int count, u8int sector, u16int cylinder, u8int *buffer) {
	u16int i, tmpword;

	outb(0x1f6, 0x0);
	outb(0x1f2, count);
	outb(0x1f3, sector);
	outb(0x1f4, 0);
	outb(0x1f5, 0);
        outb(0x1f7, 0x20);
};
[code]
i NEVER call it. It doesn't work. But if I remove that last outb-call, it works perfectly (the other code, Im still not invoking the function above).

[neon]

The LDTR is most likely not the problem if you never use it. Best recommendation I can give is to post your crash log here (more info is always better) and single step through the routine that is failing to see when it crashes.

[JohnnyTheDon]

Either your code is corrupted, or you're jumping to the middle of an instruction. How are you loading your kernel (GRUB, custom bootloader, etc.)?

[mangaluve]

I've written my own bootloader. I don't know if something get's wrong when Im loading the kernel, Im doing that in protected mode now instead of using bios interrupts.. I could post the code for the loading here, if anyone has time to look through it. I changed a little thing (removed a HLT or something after my main-function) and now I get "running in bogus memory" instead. So, by just adding the line

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outb(0x1f5, 0);

to a function that is never called, I get "running in bogus memory"


Edit: this is embarassing but I think I found it. When I copy the kernel to memory, I didn't copy the entire kernel, since it has grown since I wrote the bootloader. So sorry to bother you with my stupidity!