Another question

[Ozguxxx]

Hi everybody, I think I am about to finish about %66.66666 of my keyboard handler. (BTW abless, I inspired from your kernel alot. No copy-pasting, I got ideas. ;D Thanx.) MY question is: Is there a way to debug OS codes in some way? Almost always I try to find my errors by chance, I mean I try some code, if it doesnt work I try anohter I think many people do in the same way. Anyway I need a debugger for OS code. Thanx...

[PlayOS]

Hi,

I think what you need to do is insert a DEBUG function in your kernel and use it to print a message on the screen, add it to all of your kernel code, and insert a preprocessor around the function, to either include or exlude it

#ifdef _DEBUG_
DEBUG("Doing something in my kernel!\n");
#endif

by doing this you can build a debug version of your OS just by defining _DEBUG_ in your kernel, and a release version by leaving it out.

Hope this helps.

[Ozguxxx]

Thanx for your advice PlayOS but it is not enough for debugging asm codes. I mean I want to see what actually happens as my code goes on instruction by instruction. It is sometimes very hard to trace all asm code and sometimes the error is in part of code that you think is working... Does everybody do debugging in that way? Thanx again.

[grey wolf]

bochs comes with a run-time debigger, but it's rather awkward to use. i'm still trying to figure out how to set a breakpoint in my bootstrap code.

[dronkit]

vbreak seg:off Set a virtual address instruction breakpoint
vb seg:off lbreak addr Set a linear address instruction breakpoint
lb addr

so you would do:

Code: Select all

lb 0x7c00h

or:

Code: Select all

vb 0x07c0:0x0

here's the (kinda) manual
http://bochs.sourceforge.net/docs-html/debugger.html

[Tom]

I just use my Freeze() function to stop my code and see what's causing my probs - works great.

You can get the function at my website.
If the problem can't be froozen in the C code, try jmp $ in NASM code.

[Ozguxxx]

Thanks for bochs debugger link. I will try to understand it...