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f0dder 22 Jan 2010, 19:25
egos wrote:
I've heard claims that some systems (relatively recent ones, not talking pre-90'es or anything) don't support this system call, though... dunno if it's true, and if it is, how many machines it affects (if it's limited to high-end server BIOSes or EFI systems, I guess it's not that bad )_________________ carpe noctem |
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22 Jan 2010, 19:25 |
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egos 22 Jan 2010, 20:01
Quote: Yup, that's how I did it in my toy kernel |
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22 Jan 2010, 20:01 |
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dosin 22 Jan 2010, 21:33
egos:
Quote: Why did you this? Fill page dir with zeroes (or as I did). was just making sure the mem used is cleared... would it be best just to fill the page dir? Code: mov edi,0x5000 mov eax,0x6000 mov ecx,1024 @@: or eax,7 stosd add eax,4096 loop @b |
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22 Jan 2010, 21:33 |
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egos 23 Jan 2010, 08:20
No. Did you understand what you did? Fill page dir with zeroes and set only that dir entries which are necessary.
Code: xor eax,eax mov ecx,1024 mov edi,5000h rep stosd ... mov dword [5000h+0*4], FIRST_PAGE_TAB_ADDR or 7 |
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23 Jan 2010, 08:20 |
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dosin 23 Jan 2010, 19:55
I see - I was filling all the tables - as present.. instead of 0
So I need to set the rest of the dir to 0 and just set the ones I am using to presant.. Quote: set only that dir entries which are necessary ? What would the min dir entries should I start with? |
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23 Jan 2010, 19:55 |
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egos 23 Jan 2010, 21:42
Quote: What would the min dir entries should I start with? Code: ... lea eax,[edi-1000h+PAGE_LOCAL] mov edi,ebx stosd ; set 1st PDE mov ecx,1022 xor eax,eax rep stosd lea eax,[ebx+PAGE_LOCAL-PF_APL] stosd ; set last PDE ... |
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23 Jan 2010, 21:42 |
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dosin 01 Feb 2010, 20:40
This is messed up.. I can enable paging / long mode - 4 MB ..
works perfect every test.. but my protected mode paging crashes everytime.. I can not figure out the bug.. I will prob take a break and work on the long mode for now.. unless anyone has any sugestions.. the page table and dir fill in the same way..for the 4 MB pmode or long mode paging.. the only difference is this step to enable long mode: Code: mov ecx,0C0000080h rdmsr or eax,1 shl 8 wrmsr one crashes the other works fine..  |
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01 Feb 2010, 20:40 |
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egos 06 Feb 2010, 20:55
Quote: or do you have a small demo I could use to test...
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06 Feb 2010, 20:55 |
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egos 10 Feb 2010, 08:25
Quote: This is messed up.. I can enable paging / long mode - 4 MB .. |
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10 Feb 2010, 08:25 |
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dosin 10 Feb 2010, 16:17
Thanks for the info..
with the 32 bit paging - its writing to the video mem... and displaying junk on the screen... no matter what address I chose to start the paging at... but its not crashing like it was.. even tried your example in my kernel and same thing.. fill the screen with junk... |
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10 Feb 2010, 16:17 |
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zhak 10 Feb 2010, 20:57
egos, it would be nice if you could put comments in your source if you share it with others as a template for educational purposes.
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10 Feb 2010, 20:57 |
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egos 11 Feb 2010, 09:23
My source was intended for topic starter. If you want to see my comments show me what fragment you are interested in.
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11 Feb 2010, 09:23 |
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zhak 11 Feb 2010, 21:12
Code: mov dx,03F2h mov al,0 out dx,al cli mov al,8Fh out 70h,al in al,71h this ports operations are new for me. could you explain this part, please? |
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11 Feb 2010, 21:12 |
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f0dder 11 Feb 2010, 21:16
out(70h,8Fh) is for disabling NMIs - dunno about the rest.
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11 Feb 2010, 21:16 |
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baldr 11 Feb 2010, 21:46
zhak,
0x03F2 port is digital output register of FDC, out(0x03F2, 0) stops drives' motors, disables DMA and resets controller. |
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11 Feb 2010, 21:46 |
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zhak 11 Feb 2010, 23:30
heh, never worked with FDC. not surprised that i'm not familiar with this stuff
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11 Feb 2010, 23:30 |
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f0dder 12 Feb 2010, 06:18
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
. 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 |
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12 Feb 2010, 06:18 |
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smiddy 12 Feb 2010, 11:36
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 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. |
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12 Feb 2010, 11:36 |
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revolution 12 Feb 2010, 11:41
smiddy wrote: 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. |
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12 Feb 2010, 11:41 |
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