XIS operating system needs only 2MB of memory to run.
It supports boot loader, kernel with protected mode, paging, E820 enumeration, interrupt and exception handling, system calls and user mode.
Instructions for building kernel -
as --32 boot32.S -o boot32.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c util.c -o util.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c system.c -o system.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c apic.c -o apic.o
as --32 handlr32.S -o handlr32.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c setup32.c -o setup32.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c start.c -o start.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c memory.c -o memory.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c page32.c -o page32.o
gcc -m32 -std=gnu99 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -ffreestanding -fno-pic -Wall -Wextra -Werror -c usermode.c -o usermode.o
ld -static -T kernel32.ld -m elf_i386 -nostdlib --nmagic boot32.o util.o system.o apic.o setup32.o handlr32.o memory.o page32.o usermode.o start.o -o xiskernel.elf
objcopy -O binary xiskernel.elf xiskernel.bin
Instructions for building boot loader -
echo ".equ KERNEL_SIZE, `ls -l xiskernel.bin | cut -f5 -d\ `" > krnlsize.h
as --32 bootldr.S -o bootldr.o
ld -static -T bootldr.ld -m elf_i386 -nostdlib --nmagic -o bootldr.elf bootldr.o
objcopy -O binary bootldr.elf bootldr.bin
Creating QEMU image -
dd if=bootldr.bin of=hda.raw
dd if=xiskernel.bin of=hda.raw seek=1
qemu-img convert -O qcow2 hda.raw hda.qcow2
Running using QEMU -
sudo qemu-system-i386 -hda hda.qcow2 -m 2 --enable-kvm -cpu host
Contact -