OSDev.org

The Place to Start for Operating System Developers
It is currently Tue Feb 19, 2019 12:57 am

All times are UTC - 6 hours




Post new topic Reply to topic  [ 33 posts ]  Go to page Previous  1, 2, 3
Author Message
 Post subject: Re: drawing with VGA
PostPosted: Fri Jan 25, 2019 3:21 pm 
Offline
Member
Member

Joined: Wed Aug 29, 2018 4:42 pm
Posts: 112
ok, now trying on fonts.but it doesnt draw nothing or garbage. I.E, if i put the character is 'A' when calling the drawchar func, it doesn't do anything, and if i put the font as a character, then it draws garbage. also i have a problem between the paging and VBE, i cannot access the LFB when paging enabled(it works with paging disabled).can you help me?

Thanks!

_________________
Slidoor OS


Top
 Profile  
 
 Post subject: Re: drawing with VGA
PostPosted: Sat Jan 26, 2019 3:26 pm 
Offline
Member
Member

Joined: Fri Aug 26, 2016 1:41 pm
Posts: 329
Is your latest code (that doesn't work) in your github account? If it is, are you aware that the video mode being used is a text mode? In QEMU it is 80x25 where the LFB is at 0xb8000. I get the same result of a purplish object on the screen when 'A' is printed whether I enable paging or not (in setup.c). It ill be garbage in text mode because text mode uses 2 bytes for each cell (one character is character, and the other is the attribute). The reason LFB doesn't work is because your function id_map_lfb() is completely broken. It doesn't create proper page tables and page table entries so when you enable paging - any attemptto write to the LFB will fail.


Top
 Profile  
 
 Post subject: Re: drawing with VGA
PostPosted: Sat Jan 26, 2019 6:31 pm 
Offline
Member
Member

Joined: Wed Aug 29, 2018 4:42 pm
Posts: 112
MichaelPetch wrote:
Is your latest code (that doesn't work) in your github account?

no, it's not.i've updated the code, so now you can check it out.

MichaelPetch wrote:
The reason LFB doesn't work is because your function id_map_lfb() is completely broken. It doesn't create proper page tables and page table entries so when you enable paging - any attemptto write to the LFB will fail.


you're actually right; i was trying something to map the lfb, but it didn't actually work.

Thanks!

_________________
Slidoor OS


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 33 posts ]  Go to page Previous  1, 2, 3

All times are UTC - 6 hours


Who is online

Users browsing this forum: Bing [Bot] and 13 guests


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 post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group