Custom BIOS
gcc -c -m16 -o bios.o bios.s ld -m elf_i386 -T linker.ld -o bios.bin bios.o
https://stackoverflow.com/questions/62513643/qemu-gdb-does-not-show-instructions-of-firmware
qemu-system-i386 -bios bios.bin -device VGA,romfile="" -s -S
gdb -ix gdb_init_real_mode.txt -ex 'set tdesc filename target.xml' -ex 'target remote localhost:1234'