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ASHLEY4 27 Jan 2005, 17:03
One thing you should try is to enable A20, as with out it it will not fill the screen at high res .
_________________ \\\\||//// (@@) ASHLEY4. Batteries not included, Some assembly required. |
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27 Jan 2005, 17:03 |
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Octavio 27 Jan 2005, 17:07
try without ' add bx,4000h' ,real hardware is not very standard.
also you must use function 1 to get videomode info struct and read the video memory ptr at offset 28h |
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27 Jan 2005, 17:07 |
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joachim_neu 27 Jan 2005, 19:07
@octavio: without "add bx,0x4000" it won't work, because that sets the bit which has to be set for LFB. and as i already said am i loading the VideoMemPtr (aka PhysBasePtr) but there's only the adress of the first window in 0xA0000.
@ashley4: thank you. i don't realy understand what you're writing but i understand that i should enable A20-Gate first. i'll try it. |
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27 Jan 2005, 19:07 |
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ASHLEY4 27 Jan 2005, 19:47
Take alook at this link, same problem as yours
http://www.mega-tokyo.com/forum/index.php?board=1;action=display;threadid=6761;start=0 may help. _________________ \\\\||//// (@@) ASHLEY4. Batteries not included, Some assembly required. |
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27 Jan 2005, 19:47 |
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Octavio 27 Jan 2005, 20:05
joachim_neu wrote: @octavio: without "add bx,0x4000" it won't work, because that sets the bit which has to be set for LFB. and as i already said am i loading the VideoMemPtr (aka PhysBasePtr) but there's only the adress of the first window in 0xA0000. it works on my computers,and you are reading the videomemptr at the wrong place. |
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27 Jan 2005, 20:05 |
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joachim_neu 27 Jan 2005, 20:20
@octavio: realy? it sets the mode with LFB without adding 0x4000? i'll test it, too! but i read the pointer from the right place. it's not shown in the exaplecode, but i load it from offset 40d =0x28, and if this'd be wrong, it wouldn't run in bochs!
@ashley4: i'll have a look at it. |
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27 Jan 2005, 20:20 |
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joachim_neu 27 Jan 2005, 20:40
@ashley4: first: the link you gave me didn't help me... second: it still doesn't work, if i enable A20-gate earliear!
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27 Jan 2005, 20:40 |
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bogdanontanu 28 Jan 2005, 03:51
BTW IF you enable LFB it is NEVER going to be at 0xA0000h .
Practically is almost always above the 2Gigabyte limit. Older boards are above 1Giga byte . IF the LFB address is ok and IF you can only fill the top area of the screen THEN the video mode is banked (ie it has no LFB) so you must use a bank switching routine that is always video board dependent. Are you sure that the video bard is VESA 2.0 and NOT VESA 1.2 compatible? |
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28 Jan 2005, 03:51 |
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joachim_neu 28 Jan 2005, 08:50
@bog.: i know! often it's set to 0xe0000000, but because it's set to 0xA0000 i noticed, that something went wrong! i'm sure that it supports LFB , because MenuetOS runs with the same mode (0x115) in linearframebuffer (so the mode is 0x4115).
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28 Jan 2005, 08:50 |
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ASHLEY4 28 Jan 2005, 16:26
Your put pixel code, can you post it, as you maybe doing stosb instead of stosd.
And do you do a: Code: cmp ax,004Fhjne VesaError After doing a set vesa mode ?. _________________ \\\\||//// (@@) ASHLEY4. Batteries not included, Some assembly required. |
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28 Jan 2005, 16:26 |
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joachim_neu 28 Jan 2005, 20:03
@ashley4: i'm not always doing a "cmp ax,004Fh; jne VesaError", only after the check if VESA is availible. i test this things not with a function, but with this: "mov edi,[BasePhys];mov ecx,0x200000;mov al,0x88;rep stosb" in BasePhys i wrote the PhysicalBaseAdress. so then i set ecx to 0x200000 (for 2 MB) which must be 2/3 of the 0x118-mode oder all of the 0x115-mode.
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28 Jan 2005, 20:03 |
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joachim_neu 28 Jan 2005, 22:48
well, now i'm checking for LinearFrameBuffer during the modecheck like this:
Code: mov si,0x50 ;beginning of informationblock mov ds,si xor si,si lodsw and ax,0000000010000000b cmp ax,0000000010000000b jne near vesa_error and what i found out was that LinearFrameBuffer seems to be possible, because he didn't jump to the label. but it still doesn't work! i hope for another help, J!N |
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28 Jan 2005, 22:48 |
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ASHLEY4 29 Jan 2005, 03:18
Heres a demo i wrote to demo, how to use vesa when making a OS, try it and see the differance.
_________________ \\\\||//// (@@) ASHLEY4. Batteries not included, Some assembly required. |
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29 Jan 2005, 03:18 |
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joachim_neu 29 Jan 2005, 13:40
well, i tried your code and it runs! it runs with LFB, so my card supports LFB, i'm sure. i'll exactly search the differents to find my misstake! thank you so far!
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29 Jan 2005, 13:40 |
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joachim_neu 29 Jan 2005, 15:57
okay, i tried to set up your mode (640x480) with LFB. it doesn't work, too
 ... but ASLEY4's code works! this is my full code, i hope someone finds my misstake:
Code: ;enable vesa! push ds ;set up signature at the block at 0x50:0x00 mov di,0x50 mov es,di xor di,di mov al,'V' stosb mov al,'B' stosb mov al,'E' stosb mov al,'2' stosb xor di,di mov ax,0x4F00 int 0x10 ;get vesainformation ;check availability cmp ax,0x004F jne near vesa_error mov si,0x50 mov ds,si xor si,si lodsb lodsb cmp al,'E' jne near vesa_error mov cx,0x06 rep lodsw lodsw ;get table of modes mov bx,ax lodsw mov ds,ax mov si,bx push ds push si ;search mode (0x0118) find_right_mode1: lodsw cmp ax,0xFFFF je check_115_mode cmp ax,0x0118 jne find_right_mode1 mov bx,0x0118 jmp before_set_vesa check_115_mode: pop si pop ds ;search mode (0x0115) find_right_mode2: lodsw cmp ax,0xFFFF je near vesa_error cmp ax,0x0115 jne find_right_mode2 mov bx,0x0115 jmp set_vesa_mode before_set_vesa: pop si pop ds ;get modeinformation set_vesa_mode: mov cx,bx pop ds mov [vesa_mode],cx push ds add cx,0x4000 mov ax,0x4F01 mov di,0x50 mov es,di xor di,di int 0x10 ;read modeinformation mov si,0x50 mov ds,si xor si,si lodsw and ax,0000000010000000b cmp ax,0000000010000000b jne near vesa_error mov cx,0x0A rep lodsw lodsb lodsb pop ds mov [vesa_bits_per_pixel],al push ds mov si,0x50 mov ds,si xor si,si mov cx,0x14 rep lodsw lodsd pop ds mov [vesa_physical_base_adress],eax ;set vesamode mov bx,[vesa_mode] add bx,0x4000 mov ax,0x4F02 int 0x10 yes, that's it.... it's not very well commented, but i think it explains itself  the modeblock is written to 0x50:0x00.
thank you! J!N |
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29 Jan 2005, 15:57 |
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Octavio 29 Jan 2005, 19:39
I haven´t found any scandalous bug if direction flag =0
perhaps the bug is in another part of the code, but why you don´t use a debuger? most off us have our own sources to debug and very rarely we want to spend time debuging sources from others. and do you know that you can do de same using 1/3 of the instructions? i mean that mosts C compilers would generate better code. |
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29 Jan 2005, 19:39 |
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joachim_neu 29 Jan 2005, 20:03
@octavio: i found no error, too! but that's the problem! i know that you haven't so much time to spend in my code. i use a debugger, called bochs! and in bochs it works! that's the problem! in bochs it runs, but not so in real! and that's my problem. so i hope that anyone can help me.
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29 Jan 2005, 20:03 |
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bogdanontanu 29 Jan 2005, 22:13
to joachimneu
Well this code from solar os works also: So it might be your setting of DS at 0x50h or the fact that you request VBE2.0 ? Basically never assume that you can use what ever segments you want for BIOS ints
My buffer is at 0x0000:0x1000h . Take care as some VESA implementations do write a lot more that the 256 or 512bytes in the standards when getting info. So beware of possible overwrites on some video boards. Code: ;--------------------------- ; Detect VESA version ;--------------------------- mov ax,0 mov es,ax ;------------------------------------------ ; 4fh=VESA function ; 00=Return Super VGA Information ;------------------------------------------ mov di,1000h mov ax,04f00h int 10h ;make VESA BIOS call cmp ax,004fh ;ok value is ah=00 al=4f jz vesa_is_ok And for mode setup: Code:
mov ebx,[user_mode]
or ebx,0C000h ;clear flag+use lfb flag
mov ax,04f02h ;02-set vesa mode function
int 10h ;call VESA
or ah,ah
jnz @@fx_mode_error ;restart menu on error
Have you noticed the 0xC000h for requesting LFB and clear as opposed to your 0x4000h ... ? But that should not be an issue. I agree with Octavio here: the error is there in your code but we are unlikely to want to debug your code as we have our code to debug. So i suggest you start testing every little bit using small steep by steep and finnaly find out where the problem is. Octavio: About the C compiler generating better code, it is irelevant in this area. The guy is just making some tests and he is just a beginner ASM programmer. A C compile could never compete with me for example. Besides i like to have the inteligence to write small and fast code only when it matters. I would like the compiler to generate easy to understand code when speed doese not matter and very well optimized code where speed does matter. But a compiler has no ideea of the stage of my algorithm and the purpose for it. This is what makes HLL crippled and pathetic for ever and ever. They are usefull at times for the capitalistic world we live in but we should never praise them much, at least not on an ASM forum. There are countless forums for C/C++/Java and other abominations. And i bet members here read those forums also since we all have jobs to do. Some of the members here are C/C++ or other HLL language experts also 
Even more I have seen C compilers generating small "little devil" mistakes that only apperred in code at specifica IRQ and multi thread handling making you nuts and having to dissassemble the ASM for some exotic CPU to only find that the stupid compiler creator was unable to know a little ASM and put our job work for months at risk. Even more put lifes at risch for things i was not aware (aka C compiler mistakes) a thing that would NEVER happe if i would have written the thing in ASM originally. _________________ "Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction." |
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29 Jan 2005, 22:13 |
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joachim_neu 29 Jan 2005, 22:27
@bogdanontanu: do you think the problem is about setting DS to 0x50 or about requesting VBE2? what should i write into the signature for requesting other VESAs above? i only found VBE2 in the manuals... and i'll have a try with the segments...
EDIT: but why should it fail to write to the segments? the information are right... |
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29 Jan 2005, 22:27 |
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