flat assembler
Message board for the users of flat assembler.

Home Search Register
Log in to check your private messages Log in

Index > OS Construction > paging ?

Goto page Previous  1, 2, 3, 4
Author
Thread Post new topic Reply to topic
sinsi



Joined: 10 Aug 2007
Posts: 774
Location: Adelaide
sinsi 12 Feb 2010, 12:04
Pretty much all the BIOS timer ISR does is increment the ticks in the data area, check the fdd motor timer and turn it off if needed then call INT 1C.
If you load from fdd then do a cli the floppy motor will stay on (isn't it 5 seconds?)
Post 12 Feb 2010, 12:04
View user's profile Send private message Reply with quote
f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
f0dder 12 Feb 2010, 13:10
smiddy wrote:
f0dder wrote:
Ah yes, I see I had that 0x3F2 code in my toy kernel bootloader as well - been quite a while since I messed with it Smile. It's a good idea turning off the floppy motor if you load your kernel from floppy, before booting your kernel, otherwise you risk the light and motor keep going Smile

If I recall right, this is only if you switch processor modes. If you stay in real mode, you shouldn't need to turn the floppy off. Smile
I wouldn't use the word "kernel" if I stayed in real-mode Wink

But yes, staying in RM and not CLI'ing, it would turn off automagically.

_________________
Image - carpe noctem
Post 12 Feb 2010, 13:10
View user's profile Send private message Visit poster's website Reply with quote
asmmsa



Joined: 06 Feb 2010
Posts: 45
asmmsa 12 Feb 2010, 15:39
im not there yet in details, but paging is basicly simple.

CR3 holds pointer to first element of table.

x86
x86 PAE
x86 PSE
x86_64


all have diffrent tables
when you switch to 1 of those moeds, you have to prepare specyfic page table.


translation is basicly index in that table = virtual address, and under it u have physical mapping.
Post 12 Feb 2010, 15:39
View user's profile Send private message Reply with quote
smiddy



Joined: 31 Oct 2004
Posts: 557
smiddy 12 Feb 2010, 20:36
Exactly! Smile
Post 12 Feb 2010, 20:36
View user's profile Send private message Reply with quote
smiddy



Joined: 31 Oct 2004
Posts: 557
smiddy 12 Feb 2010, 20:38
f0dder wrote:
I wouldn't use the word "kernel" if I stayed in real-mode Wink

But yes, staying in RM and not CLI'ing, it would turn off automagically.

Ah, where's my head at, kernel meaning !RM...Very Happy
Post 12 Feb 2010, 20:38
View user's profile Send private message Reply with quote
egos



Joined: 10 Feb 2009
Posts: 144
egos 13 Feb 2010, 07:05
f0dder wrote:
out(70h,8Fh) is for disabling NMIs - dunno about the rest.
baldr wrote:
0x03F2 port is digital output register of FDC, out(0x03F2, 0) stops drives' motors, disables DMA and resets controller.
Oh, thanks! You made my job instead of me Smile

f0dder wrote:
Ah yes, I see I had that 0x3F2 code in my toy kernel bootloader as well - been quite a while since I messed with it Smile. It's a good idea turning off the floppy motor if you load your kernel from floppy, before booting your kernel, otherwise you risk the light and motor keep going Smile
It is a good idea even if booting occurred from non-floppy media Wink
Post 13 Feb 2010, 07:05
View user's profile Send private message Reply with quote
f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
f0dder 13 Feb 2010, 07:22
egos wrote:
It is a good idea even if booting occurred from non-floppy media Wink
Oh? How come?

_________________
Image - carpe noctem
Post 13 Feb 2010, 07:22
View user's profile Send private message Visit poster's website Reply with quote
baldr



Joined: 19 Mar 2008
Posts: 1651
baldr 13 Feb 2010, 08:31
f0dder,

Are you joking? 99.(9) % of machines are booting off non-floppy media. Wink
Post 13 Feb 2010, 08:31
View user's profile Send private message Reply with quote
f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
f0dder 13 Feb 2010, 08:33
baldr wrote:
f0dder,
Are you joking? 99.(9) % of machines are booting off non-floppy media. Wink
Yes, they are... I was wondering why egos recommends issuing the FDC command even when not booting from floppy media Smile

_________________
Image - carpe noctem
Post 13 Feb 2010, 08:33
View user's profile Send private message Visit poster's website Reply with quote
baldr



Joined: 19 Mar 2008
Posts: 1651
baldr 13 Feb 2010, 08:35
f0dder,

I second that. He should check the presence of FDC beforehand. Wink
Post 13 Feb 2010, 08:35
View user's profile Send private message Reply with quote
egos



Joined: 10 Feb 2009
Posts: 144
egos 13 Feb 2010, 10:45
BIOS checks on existing floppy disk in the drive by reading it (i.e. with turning on the motor). If you have boot sequence "FDD, HDD" and there is no floppy disk in the drive at boot time then BIOS would try to boot the system from hard drive, but the motor could stay turned on. I have no floppy drive (but FDC is present), however this command is accepted well.
Post 13 Feb 2010, 10:45
View user's profile Send private message Reply with quote
smiddy



Joined: 31 Oct 2004
Posts: 557
smiddy 13 Feb 2010, 14:24
I would contend...

Your OS should check for all hardware, catalog it (in a form your OS knows), reset it (nominally and minimally) to the quiescent state(s), making them ready to use for your OS, at start up, in my opinion.

-smiddy
Post 13 Feb 2010, 14:24
View user's profile Send private message Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  
Goto page Previous  1, 2, 3, 4

< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Main index Download Documentation Examples Message board

Copyright © 1999-2023, Tomasz Grysztar. Also on GitHub, YouTube, Twitter.

Website powered by rwasa.