problem in linking Bkerndev

[mar-rih]

Hi....

I try to build the bkerndev, the toutorial in Boanfide site

http://osdever.net/bkerndev/index.php?the_id=90

but this bug apear to me when Likage try to link the kernel....

G:\Projects\Marwan\Operating System\Rsources\startker\1\Sources>ld -T link.ld -o
tools/kernel.bin obj/main.o obj/scrn.o obj/gdt.o obj/idt.o obj/isrs.o obj/irq.o
obj/timer.o obj/start.o obj/kb.o
obj/start.o: file not recognized: File format not recognized

could anybody interpret this problem please....

[distantvoices]

@admin: could you move this to osdev section? thx.

@mar-rih: the object file you have supplied is in a format which thelinker canna interpret. It does know about certain formats, but 1. you have to stick to one object format, and 2. if you have told f. ex. nasm to create a binary object file, this won't link to any other object files - so the linker might have a valid reason to refuse linking.

Just give us the script with which you are compiling the stuff.

Maybe we can get the knack together.

[mar-rih]

The format of the file is -aout

the building command for the kernel is thes

nasm -f aout boot/start.asm -o obj/start.o

gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/main.o ker/main.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/scrn.o ker/scrn.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/gdt.o ker/gdt.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/idt.o ker/idt.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/isrs.o ker/isrs.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/irq.o ker/irq.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/timer.o ker/timer.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o obj/kb.o ker/kb.c

ld -T link.ld -o tools/kernel.bin obj/main.o obj/scrn.o obj/gdt.o obj/idt.o obj/isrs.o obj/irq.o obj/timer.o obj/start.o obj/kb.o

and i have attached the link file...

[Curufir]

Well the problem seems to lie with start.o.

Try using ELF or COFF as the nasm option instead of AOUT.

[mar-rih]

Well the problem seems to lie with start.o.

Try using ELF or COFF as the nasm option instead of AOUT.

i changed the Format of output file, to COFF and ELF but another error at linkage

this message appear when linking

Code: Select all

ld -T link.ld -o tools/kernel.bin obj/main.o obj/scrn.o obj/gdt.o obj/idt.o obj/isrs.o obj/irq.o obj/timer.o obj/start.o obj/kb.o

ld: PE operations on non PE file.

[Pype.Clicker]

that sounds typical from a cygwin/mingw installation that only supports windows .EXE files. The best we have found to work this out is to build yourself a proper CrossCompiler that will support your target environment (be it ELF, COFF or whatever).

You should find help about it in the FAQ (click the large "megatokyo.com" banner above )

[mar-rih]

My problem until now did not solved...!!!!

@Pype.Clicker :
i can't understand your last reply...
and i have gone at the Link in OS-FAQ and read the page..

do you mean that my compiler MinGw is the Problem ?
do you mean i must uninstall mingw and install djpp instead ?

[Pype.Clicker]

indeed, i think your MingW is the problem. I don't suggest DJGPP, but rather CYGWIN.

More precisely, i suggest you get CYGWIN and *then* rebuild a compiler suitable to OsDev using that CYGWIN.

It may sound scary, but compared to what i had to do to get kernel loaded using DJGPP and tools of mine, it's piece of cake

[calpis]

Hi, I had the same problem with Bkerndev linking as well. I needs some help please.

I did nasm -f aout -o start.o start.asm and it created start.o
But when i try to link it with other object files, only start.o has generate this error message

start.o : file not recognized: File format not recognized

Then I changed the file format to elf and coff.
It generated so many error message saying undefined reference in functions 'stublet', _gdt_flush and all the rest of it.

I m using a cross complier gcc3.4.2 (mingw special) on osx. Targeted for i586-elf. I hope that the problem doesn't reside on mingw special. Coz it worked fine when I tried with loader.s instead of start.asm.

I think the problem might be my nasm. I complied it with --target to i586-elf...is it correct?

[Kim]

You have to use elf format as output format for nasm, when using an linker that needs elf objects as input.

nasm -f elf -o start.o start.asm

The stub and linker script on that link can not be used for an elf format kernel.

There's an GRUB elf format kernel barebone on the FAQ.

Make sure you have a crosscompiled gnu linker to elf format.

http://www.osdev.org/osfaq2/index.php/BareBones?PHPSESSID=422099fc65fd7d6dff90e1a4cb3a2b84
http://www.osdev.org/osfaq2/index.php/NasmAllInOne#loaderx2ex2e.s
http://www.osdev.org/osfaq2/index.php/GCC%20Cross-Compiler?PHPSESSID=422099fc65fd7d6dff90e1a4cb3a2b84

[calpis]

Thanks, Yeah, I did that, and it kind of work after I removed or add the underscores to tackle the undefined references.