[Closed] Setting VESA/VBE Mode

[Octacone]

Update:
I downloaded and included multiboot header file.

kernel_main(multiboot_info_t *mbit)
{
...
}

Now how do I set mbit.width and mbit.height mbi.mod_type mbi.depth?
I can not do that directly because compiler throws errors.
Is there any special assembly related code I need to do before that?

Update 2: I just discovered that you can set multiboot flags inside assembly and that they co-respond with those declared inside my C file.
Since I am using NASM I can not use stuff like .long and .set and I need to use equ and dd but I can not compiler that.

Update 3: I set all the flags for my graphics mode and trust me nothing happens:

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section         .text
        align 4
    dd MAGIC
    dd FLAGS
    dd CHECKSUM
    dd 0
    dd 0
    dd 0
    dd 0
    dd 0
    dd 0
    dd 1360
    dd 768
    dd 32

Exaclty the same problem !
i'm sure you use grub legacy do you ?
You need grub 2 or a patched version of grub legacy

And add that to your grub.cfg file:

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insmod vbe
insmod vga

Wow, I do not have grub.cfg file. That is really weird, my grub does not want to create an iso image for my OS.

[DeezRamChips]

So, here is how you do:

Step 1:
Create a Directory names "iso"

Step 2:
Put your compiled kernel in this directory

Step 3:
in this directory (iso) create a sub directory called "boot" and in that directory (boot) create a sub directory called "grub"

You should now have something like:

Code: Select all

iso/boot
iso/boot/grub
iso/kernel.bin

Step 4:
in the directory iso/boot/grub , create a file called grub.cfg and write this in it:

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set default=0
set timeout=0
insmod vbe
insmod vga
menuentry "nameOfYourOs" {	
  multiboot /yourKernel.bin
  boot
}

Step 5:
In the terminal type:

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sudo grub-mkrescue --output=boot.iso iso

Here you go ^_^

[DeezRamChips]

And here is how you plot a pixel: (it's the vesa driver I just wrote )

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#include <vesa.h>
#include <types.h>
#include <io.h>

long fb_addr;
int fb_pitch;
int fb_width;
int fb_height;
char fb_bpp;

char* vram = (char*)0xB8000;

void init(long addr, int pitch, int width, int height, char bpp){
	vram = (char*)addr;
	fb_pitch = pitch;
	fb_width = width;
	fb_height = height;
	fb_bpp = bpp;
}

void putPixel(int x, int y, int r, int g, int b){
    unsigned where = x*pitch + y*fb_width;
	vram[where + 0] = b;  // BLUE
    vram[where + 1] = g;  // GREEN
    vram[where + 2] = r;  // RED
	vram[where + 3] = 0xFF;  // ALPHA
}

[DeezRamChips]

Wowowow there is and error in the vesa drive, let me correct it

[Octacone]

So, here is how you do:

Step 1:
Create a Directory names "iso"

Step 2:
Put your compiled kernel in this directory

Step 3:
in this directory (iso) create a sub directory called "boot" and in that directory (boot) create a sub directory called "grub"

You should now have something like:

Code: Select all

iso/boot
iso/boot/grub
iso/kernel.bin

Step 4:
in the directory iso/boot/grub , create a file called grub.cfg and write this in it:

Code: Select all

set default=0
set timeout=0
insmod vbe
insmod vga
menuentry "nameOfYourOs" {	
  multiboot /yourKernel.bin
  boot
}

Step 5:
In the terminal type:

Code: Select all

sudo grub-mkrescue --output=boot.iso iso

Here you go ^_^

Interesting, I've already had a setup like this. Now I added those two commands to grub.cfg and nothing, my .iso does not get created for some reason. What do you use for your emulator. I use qemu-system-i386 with -vga std flag and then I just get no bootable media can't boot from cd floppy hdd etc, but when I use -kernel it works but only kernel shell without any graphics mode.

[DeezRamChips]

Yes, qemu does not work with grub for some reason, i'm using Oracle Virtual Box 4.1

EDIT: No, it works fine now lol, You CAN use qemu

[Octacone]

Yes, qemu does not work with grub for some reason, i'm using Oracle Virtual Box 4.1

EDIT: No, it works fine now lol, You CAN use qemu

What flags do you use (for qemu)?
Can you show me a screenshot of your working GUI?

[DeezRamChips]

I dont have a working gui yet, but I plot pixels at the right place.
and, here is the qemu command:

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qemu boot.iso -vga std

[DeezRamChips]

Could you try the the grub command with my iso directory, it's in an attachement

[Octacone]

Could you try the the grub command with my iso directory, it's in an attachement

I will try to boot that file, but first I need to make an iso from it using grbu.

[DeezRamChips]

well, it's in the iso.zip file (I gave you my "iso" directory).
have you installed grub 2 or grub legacy

try:

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sudo apt-get install grub2

[Octacone]

well, it's in the iso.zip file (I gave you my "iso" directory).
have you installed grub 2 or grub legacy

try:

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sudo apt-get install grub2

Looks like I was using grub legacy....
I started connection the peaces together.

[Octacone]

Okay:
1.Grub2 is installed
2.I have a folder inside my osdev one called iso insde it I have folder called boot inside boot I have grub.cfg and my os compiles into an image called kernel.bin that is located inside iso folder and that qemu uses to boot from
3.When I boot that kernel.bin with qemu without -kernel flag I get no boot media and stuff like that = can not boot anything
4.My grub still does not want to make .iso file
5.Looks like there is more into it then I thought

[Octacone]

Code: Select all

Here is my makefile:
COMPILER = gcc
LINKER = ld
ASSEMBLER = nasm
CFLAGS = -m32 -c -ffreestanding -O2 -Wall -Wextra -std=gnu99 
ASFLAGS = -f elf32
LDFLAGS = -m elf_i386 -T src/link.ld
EMULATOR = qemu-system-i386
EMULATOR_FLAGS = -vga std  

OBJS = not important
OUTPUT = iso/kernel.bin

run: all
	$(EMULATOR) $(EMULATOR_FLAGS) $(OUTPUT)

all:$(OBJS)
	mkdir iso/ -p
	mkdir iso/boot/ -p
	$(LINKER) $(LDFLAGS) -o $(OUTPUT) $(OBJS)

obj/etc.o:src/etc.asm
	$(ASSEMBLER) $(ASFLAGS) -o obj/etc.o src/kernel.etc   my way of compiling etc does not matter for this case cause it works

build:all
	rm iso/boot/grub/ -r -f
	mkdir iso/boot/grub/
	echo set default=0 >> iso/boot/grub/grub.cfg
	echo set timeout=0 >> iso/boot/grub/grub.cfg
	echo menuentry "BasicOS" { >> iso/boot/grub/grub.cfg
	echo         set root='(hd96)' >> iso/boot/grub/grub.cfg
	echo         multiboot /boot/kernel.bin >> iso/boot/grub/grub.cfg
	echo } >> iso/boot/grub/grub.cfg

	grub-mkrescue -o BasicOS.iso iso/
	
clear:
	rm -f obj/*.o
	rm -r -f iso/

My folder tree:
iso/boot/grub/grub.cfg
iso/kernel.bin //this is where my os gets compiled

[DeezRamChips]

do you want that I upload my os so you can try to compile it ?(the build.sh also creates the iso)

If my os compiles, I means you have an error of some sort :/