I'm pretty new to OS Developement, but I'm quite interested and I'm trying to start with a simple kernel, which isn't made by me, but which I copied from the tutorial in OS Developing from http://www.osdever.net/bkerndev/index.php
I can compile it, but I can't link it correctly, so whenever I try to link it I get the error message:
Actually I don't really understand what the problem could be, since I followed the tutorial step by step. I'm using NASM and LD GNU Linker(latest version I found on the net). Anyway, I'll post here the ASM code I'm using and my makefile.kernel.o: file not recognized: File format not recognized
kernel.asm:
Code: Select all
; This is the kernel's entry point. We could either call main here,
; or we can use this to setup the stack or other nice stuff, like
; perhaps setting up the GDT and segments. Please note that interrupts
; are disabled at this point: More on interrupts later!
[BITS 32]
global start
start:
mov esp, _sys_stack ; This points the stack to our new stack area
jmp stublet
; This part MUST be 4byte aligned, so we solve that issue using 'ALIGN 4'
ALIGN 4
mboot:
; Multiboot macros to make a few lines later more readable
MULTIBOOT_PAGE_ALIGN equ 1<<0
MULTIBOOT_MEMORY_INFO equ 1<<1
MULTIBOOT_AOUT_KLUDGE equ 1<<16
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_AOUT_KLUDGE
MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
EXTERN code, bss, end
; This is the GRUB Multiboot header. A boot signature
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd MULTIBOOT_CHECKSUM
; AOUT kludge - must be physical addresses. Make a note of these:
; The linker script fills in the data for these ones!
dd mboot
dd code
dd bss
dd end
dd start
; This is an endless loop here. Make a note of this: Later on, we
; will insert an 'extern _main', followed by 'call _main', right
; before the 'jmp $'.
stublet:
jmp $
; Shortly we will add code for loading the GDT right here!
; In just a few pages in this tutorial, we will add our Interrupt
; Service Routines (ISRs) right here!
; Here is the definition of our BSS section. Right now, we'll use
; it just to store the stack. Remember that a stack actually grows
; downwards, so we declare the size of the data before declaring
; the identifier '_sys_stack'
SECTION .bss
resb 8192 ; This reserves 8KBytes of memory here
_sys_stack:
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echo Now assembling, compiling, and linking your kernel:
nasmw -f aout kernel.asm -o kernel.o
rem Remember this spot here: We will add 'gcc' commands here to compile C sources
rem This links all your files. Remember that as you add *.o files, you need to
rem add them after start.o. If you don't add them at all, they won't be in your kernel!
ld -T link.ld -o kernel kernel.o
echo Done!
pause
Any help is welcome
