OSDev.org

Posted: **Sat Jun 18, 2022 10:55 am**

i was trying to follow the bare bones tutorial with c++
i think the problem might be with my makefile so im gonna put it here

Code: Select all

C_SOURCES = $(wildcard kernel/*.cpp libk/*.cpp libc/*.cpp)
HEADERS = $(wildcard kernel/*.hpp libk/*.hpp libc/*.hpp)
OBJ = ${C_SOURCES:.cpp=.o}

CC = i686-elf-g++
GDB = i686-elf-gdb
CFLAGS = -g -m32 -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs \
		 -Wall -Wextra -fcommon

run: iota.iso
	qemu-system-i386 -cdrom iota.iso
	
iota.iso: kernel.bin
	cp kernel.bin isodir/boot/kernel.bin
	grub-mkrescue -o iota.iso isodir

kernel.bin: boot.o ${OBJ}
	i686-elf-ld -o $@ -T linker.ld $^ --oformat binary

boot.o: boot.s
	i686-elf-as boot.s -o boot.o

%.o: %.cpp ${HEADERS}
	${CC} ${CFLAGS} -ffreestanding -c $< -o $@

clean:
	rm ${OBJ} iota.iso kernel.bin

i tried copying the boot.s code from the wiki page but it still keeps giving me the error
it might also be the c++ code so im gonna put that there too

Code: Select all

//
//  kernel.cpp
//  iota
//
//  Created by Anthony Valdes on 2022-06-17.
//

#include "kernel.hpp"

extern "C" void kmain(void) {
    
}

the kernel.hpp file is empty apart from an include guard and the comment at the start

Posted: **Sun Jun 19, 2022 5:45 pm**

Code: Select all

kernel.bin: boot.o ${OBJ}
   i686-elf-ld -o $@ -T linker.ld $^ --oformat binary

If you're using the boot.s from the Bare Bones template on the wiki, it does not set up the Multiboot header with necessary information for making a flat binary readable by Grub - its Makefile builds an ELF binary, but your use of --oformat binary produces a raw binary. If this is what you want to do, you'll need to adjust the header you build to set the appropriate flag to tell Grub the address section of the Multiboot header is valid, and to set the appropriate values in it. You can read more about those entries in the header here: https://www.gnu.org/software/grub/manua ... ess-fields

Additionally, you should not set CC to a C++ compiler in a Makefile, and not all C sources will compile as C++, so be careful with that.

Posted: **Mon Jun 20, 2022 10:16 am**

thanks i noticed that mistake before so i removed it and changed my makefile to use c instead of c++

OSDev.org

error: invalid arch-dependent ELF magic when using grub

error: invalid arch-dependent ELF magic when using grub

Re: error: invalid arch-dependent ELF magic when using grub

Re: error: invalid arch-dependent ELF magic when using grub