Help me boot my kernel

[ksk]

My Problem:
----------

I have these files

Kernel.c
--------

void print(char *text)
{
char *vidmem = (char *)0xB8000;

while(*text != 0)
{
  *vidmem = *text;
  vidmem++;
  *vidmem = 0x07;
  vidmem++;
  text++;
}

}

void Dmain()
{
print("Hello World !!!");
}


Start.asm
---------
extern _Dmain
global _main

[SEGMENT .text]
[BITS 32]

_main:
        call _Dmain
        mov ax,0x0
        ret
        hlt


link.ld
-------
SECTIONS
{
  .text 0x00100000 :
  {
   *(.text)
  }

}


---------------------

Now I created coff files from these files and they are kernel.o and start.o.

And then I linked them using ld using the following command

ld -T link.ld kernel.o start.o --oformat binary -o kernel.bin

Now when I try to load my kernel I get a triple fault exception (definitely not what I expected).

I don't know what's the problem - something tells me that the problem is in my linker script.

Can someone tell me how to get 16-bit output from gcc( I tried the asm(".code16gcc") - didn't work)

Please help me.


cheers

ksk

[Ramanan]

Hi,
1)
-        call _Dmain
-        mov ax,0x0
-        ret     // this may not be needed, it may coz reboot if u r in pmode
-        hlt

2) if u r losding the kernel after setting up the pmode, then u have to use the seg selector to write 2 the video memory, u shouldn't write like this.

   it doesn't matter if u r producing 16 or 32 bit code, better write ur own bootloader.

rgds,
YogaRamanan.T

[Neo]

I dont think you should have the
mov ax,0
ret
instead use
cli
hlt

and try using GRUB to boot the file

[SystemHalted]

Dont forget the entry point in the linker script

[SystemHalted]

After actually reading your code just put ENTRY(_main) in your linker script.
Also in your link.ld you should have this OUTPUT_FORMAT("binary")
so link.ld should look like this
OUTPUT_FORMAT("binary")
ENTRY(_main)

SECTIONS
{
  .text 0x00100000 :
  {
   *(.text)
  }

}
also your linking it wrong:
ld -T link.ld start.o kernel.o --oformat binary -o kernel.bin
that is the right way.

or if you want it all in one file you could do this

void Dmain(void)
{
        print("Hello, World\n");
        asm(
        "mov %ax,$0      \n"
        "cli \n"
        "hlt");
}
and in link.ld
ENTRY(_Dmain)
and you wouldnt need start.asm
I did it in my kernel and it works fine
Althought its just a suggestion.

Good Luck
--KERNEL PANIC--
SystemHalted