Search found 14 matches

by Annie
Mon Apr 12, 2010 11:34 pm
Forum: Assembly Language
Topic: Some silly Assembly question
Replies: 3
Views: 18308

Re: Some silly Assembly question

Thanks for the reply, the org 0x10000 is found in tutorial 11, the asm file of stage 3. About bpbBytesPerSector, why is there sometimes ":" for declaration, and sometime don't. (I know ":" is added at the end of a lablel) ex: someVaraible db 10 msg db "message here" bpbBytesPerSector: db 512 why don...
by Annie
Mon Apr 12, 2010 12:01 pm
Forum: Assembly Language
Topic: Some silly Assembly question
Replies: 3
Views: 18308

Some silly Assembly question

Hi, Can anyone explain to me why org 0x10000 ; the file start at 1MB why is 0x10000 = 1MB? 0x10000 = 65536 in decimal. isn't it be 1Kb One more question is that Its not variable declaration. so what this line means? it looks line a label but with value! bpbBytesPerSector: DW 512 Thank you
by Annie
Thu Apr 08, 2010 11:27 am
Forum: Beginning OS Development
Topic: Prepare Kernel 2 Question
Replies: 2
Views: 9603

Prepare Kernel 2 Question

Hi, Could anyone please explain to me why we do this %define ROOT_OFFSET 0x2e00 %define FAT_SEG 0x2c0 %define ROOT_SEG 0x2e0 I know that each Fat has 9 sectors, (512 bytes per sector), so each Fat has 4608 bytes. However, the gap between FAT_SEG and ROOT_SEG is only 32 bytes. Will the FAT data overr...
by Annie
Fri Apr 02, 2010 9:31 pm
Forum: Beginning OS Development
Topic: gdt and pmode problem
Replies: 12
Views: 18733

Re: gdt and pmode problem

hi thanks, the basic rules help.

Just to make sure I understand thing correctly

if we are actually out by 0x5000, how could the codes still run fine?

why 0x5500 (linear address) is going to 0x500 linear?

Thanks
by Annie
Fri Apr 02, 2010 9:43 am
Forum: Beginning OS Development
Topic: gdt and pmode problem
Replies: 12
Views: 18733

Re: gdt and pmode problem

HI, Thanks I think I kind of understand. Now I understand why we need to set those segment and org in gdt. Just one more question regarding the ip and cs (an example Andyhhp showed) so if we set ORG to 0x500, our ip value will be added to 0x500. Our code stage2 is loaded at 0x500. and as exor said, ...
by Annie
Thu Apr 01, 2010 12:07 pm
Forum: Beginning OS Development
Topic: gdt and pmode problem
Replies: 12
Views: 18733

Re: gdt and pmode problem

hi,

one more question (sorry for asking such a silly but I couldnt find it on google),

"org" directive add the given value to CS, DS, ES... DI, SI right?

Thanks
by Annie
Thu Apr 01, 2010 12:00 pm
Forum: Beginning OS Development
Topic: gdt and pmode problem
Replies: 12
Views: 18733

Re: gdt and pmode problem

hi Andyhhp, Thanks for the explanation but I have a question, if the code (stage 2 is loaded at 0050:0000), Will the code segment (cs) is set to 0x0500 (or it is 0 and we need to have the org directive (0x500) to add to it?) I remember in the stage 2 of the bootloader 4 (Tut 6), we set "org 0", and ...
by Annie
Mon Mar 29, 2010 12:55 am
Forum: Beginning OS Development
Topic: CS Address of GDt
Replies: 1
Views: 5942

CS Address of GDt

Hi, I need help. In Tutorial 8, the section where we need to make a far jump to fix the CS address (making sure it contains the Code descriptor address) cli ; clear interrupts mov eax, cr0 ; set bit 0 in cr0--enter pmode or eax, 1 mov cr0, eax jmp 08h:Stage3 ; far jump to fix CS. Remember that the c...
by Annie
Tue Mar 16, 2010 10:58 am
Forum: Beginning OS Development
Topic: Boch Debugging
Replies: 3
Views: 8632

Re: Boch Debugging (Revisit)

hi, thank a lot for the link. I have another question regarding Bochs Debug. Suppose that inside your code you have a function, say Print and its called in the main program. Now if you are stepping the code with Bochs debug, when get to the function call, it will step into the function. Is there awa...
by Annie
Thu Mar 04, 2010 10:26 am
Forum: Beginning OS Development
Topic: Boch Debugging
Replies: 3
Views: 8632

Boch Debugging

Hi Mike, I like the series very much, and trying to follow it. However, I have a request. Maybe when you got time you can add to the series. It is a chapter to teach how to debug in boch. Sometimes when I ran into problems it is such a pain to find out what is wrong. I guess some knowledge of debugg...
by Annie
Fri Apr 24, 2009 1:56 am
Forum: Beginning OS Development
Topic: Totorial 20
Replies: 13
Views: 26966

Re: Totorial 20

cant wait ... 8)
by Annie
Sun Mar 15, 2009 10:46 pm
Forum: Beginning OS Development
Topic: Totorial 20
Replies: 13
Views: 26966

thanks Mike, I am looking forward to it
by Annie
Thu Mar 12, 2009 4:17 am
Forum: Beginning OS Development
Topic: Totorial 20
Replies: 13
Views: 26966

Totorial 20

I really dont mean to rush, just want to know when about the tutorial 20 is available?

I just finished tutorial 19 and can wait to go to the next. 8)

I do know that it takes much longer to prepare a tutorial than to study it, so again no rushing :roll:

Thank alot, Mike
by Annie
Thu Feb 12, 2009 10:11 pm
Forum: Beginning OS Development
Topic: Demo quetion
Replies: 2
Views: 7268

Demo quetion

Hi, I have visual studio 2008 installed on my PC, will all the demo work with VS 2008? or I have to setup the right version