Search found 18 matches

by afdgdhfrtewdszs
Thu May 09, 2013 9:55 am
Forum: Beginning OS Development
Topic: IDT installing help
Replies: 2
Views: 8812

Re: IDT installing help

Thanks for your help, keep up the good word!
by afdgdhfrtewdszs
Mon May 06, 2013 11:18 pm
Forum: Beginning OS Development
Topic: IDT installing help
Replies: 2
Views: 8812

IDT installing help

Hello, is it necessary to install processor exceptions(with interrupt number 0-31) while installing IDT? Thanks.
by afdgdhfrtewdszs
Sun Mar 17, 2013 8:32 am
Forum: Beginning OS Development
Topic: kernel format
Replies: 2
Views: 7430

Re: kernel format

Thanks for the response, it just didn't cross my mind.
by afdgdhfrtewdszs
Thu Mar 14, 2013 12:28 am
Forum: Beginning OS Development
Topic: kernel format
Replies: 2
Views: 7430

kernel format

I would like to ask why do we have to(or choose to) compile kernel with pe or elf formats and we don't just compile it as flat binary format(pure binary). What are the steps required to compile and load kernel as elf format?
by afdgdhfrtewdszs
Fri Nov 30, 2012 12:55 am
Forum: Beginning OS Development
Topic: Segments initiation problem
Replies: 1
Views: 6513

Segments initiation problem

Hi, I am confused at the point where we set registers as soon as we into protected mode. Especially when setting stack-segment with the same selector as data-segment. This means that they will have the same base-limit address. My question is this: Stack,data and code won't 'interfere' with each othe...
by afdgdhfrtewdszs
Wed Nov 28, 2012 10:57 pm
Forum: Beginning OS Development
Topic: GDT help
Replies: 8
Views: 13151

Re: GDT help

Thanks a lot! Really helpful!
by afdgdhfrtewdszs
Wed Nov 28, 2012 9:09 am
Forum: Beginning OS Development
Topic: GDT help
Replies: 8
Views: 13151

Re: GDT help

Hi, Thanks again for your valuable help. If the OS wants to give control to a program(and needs to go to user-mode), once program finishes its execution and want to give control back to OS, how will OS go to ring-0 since it can't go from ring-3 to ring-0? Is 'jmp 0x8:Stage2' the same with the follow...
by afdgdhfrtewdszs
Mon Nov 26, 2012 11:57 pm
Forum: Beginning OS Development
Topic: GDT help
Replies: 8
Views: 13151

Re: GDT help

RPL is only for ds?How do we initially set CPL?
by afdgdhfrtewdszs
Sun Nov 25, 2012 10:25 am
Forum: Beginning OS Development
Topic: GDT help
Replies: 8
Views: 13151

Re: GDT help

Hi, thanks for the response but i still have a couple of questions. In number 0x10(0000000000010 0 00) index is 10(2), so null-descriptor is at index 0 and code-descriptor is at index 1? In addition 0x8 and 0x10 are not what they are because they are equal to the bytes from the start of the GDT, but...
by afdgdhfrtewdszs
Fri Nov 23, 2012 12:20 am
Forum: Beginning OS Development
Topic: GDT help
Replies: 8
Views: 13151

GDT help

Hello, i have some questions about selectors. First of all i found that a selector(segment register) contains a 13-bit index,1-bit identification for GDT/LDT and 2-bits for protection level. After we entered protected mode and jump to Stage3, we loaded only descriptor index(0x10) in segments. Why we...
by afdgdhfrtewdszs
Mon Oct 29, 2012 10:53 pm
Forum: Beginning OS Development
Topic: Bootloader instructions help
Replies: 3
Views: 8445

Re: Bootloader instructions help

Thanks for your help, here is the code:

xor ax, ax
mov ds, ax
mov es, ax
by afdgdhfrtewdszs
Mon Oct 29, 2012 12:10 pm
Forum: Beginning OS Development
Topic: Bootloader instructions help
Replies: 3
Views: 8445

Bootloader instructions help

Hello i don't understand why we need to disable interrupts(with cli), i thought using hlt(to halt the cpu would be enough). In addition why do we need to null ds and es?
by afdgdhfrtewdszs
Thu Feb 10, 2011 3:43 pm
Forum: Beginning OS Development
Topic: Problem with bootloader
Replies: 8
Views: 9604

Re: Problem with bootloader

Thank you very much for your time.I didn't provide more information because i didn't use Bochs (instead i 'm using VirtualBox).I installed it and boot from the floppy (the one where the boot loader and and second stage file are locatedn) but Bochs just hung up without even printing any info in the l...
by afdgdhfrtewdszs
Wed Feb 09, 2011 10:13 pm
Forum: Beginning OS Development
Topic: Problem with bootloader
Replies: 8
Views: 9604

Re: Problem with bootloader

Problem not fixed yet.
by afdgdhfrtewdszs
Wed Feb 09, 2011 11:38 am
Forum: Beginning OS Development
Topic: Problem with bootloader
Replies: 8
Views: 9604

Re: Problem with bootloader

The problem is that it doesn't load and execute stage 2 bootloader.