# Used to generated .d file that deal with header dependencies
CPPFLAGS = -MMD
AS=nasm
ASFLAGS += -f elf32
LDFLAGS += -m elf_i386
CFLAGS += -m32 -Wall -Wextra -Werror -ffreestanding -fno-exceptions -fno-pie -fno-stack-protector -fno-tree-vectorize
CXXFLAGS += -m32 -Wall -Wextra -Werror -ffreestanding -fno-exceptions -fno-rtti -fno-pie
DEBUG_FLAGS += -g -Og -DDEBUG -fno-omit-frame-pointer -fno-inline
LIBGCC = $(shell $(CC) -print-libgcc-file-name $(CFLAGS))

QEMU_OPT += -hda disk.img
ARCH?=x86
SUBDIRS := core drivers tests arch/$(ARCH)

INCDIRS += $(foreach dir, $(SUBDIRS), -I$(dir))
CPPFLAGS += $(INCDIRS)

asmsrc=
asmobj=$(asmsrc:%.asm=%.o)
gasmsrc=$(wildcard arch/$(ARCH)/*.S arch/$(ARCH)/boot/*.S)
gasmobj=$(gasmsrc:%.S=%.o)
csrc=$(shell find $(SUBDIRS) -type f -name "*.c")#   $(wildcard *.c)
cobj=$(csrc:%.c=%.o)
deps=$(csrc:%.c=%.d) $(gasmsrc:%.S=%.d)

kernel kernel.sym &: $(asmobj) $(gasmobj) $(cobj) linker.ld
	$(LD) $(LDFLAGS) $(asmobj) $(gasmobj) $(cobj) -o kernel -T linker.ld $(LIBGCC)
	objcopy --only-keep-debug kernel kernel.sym
	objcopy --strip-debug  kernel

fd.iso: kernel
	mkdir -p isodir/boot/grub
	cp $< isodir/boot/
	@printf "menuentry \"myos\" {\n\tmultiboot /boot/kernel\n}" > isodir/boot/grub/grub.cfg
	grub-mkrescue -o $@ isodir

disk.img: disk.sfdisk
	qemu-img create -f raw $@ 32M
	sfdisk $@ < disk.sfdisk

# NASM without preprocessing
%.o:%.asm
	$(AS) $(ASFLAGS) -o $@ $<

#GNU GAS ASM with C Preprocessing
%.o: %.S
	$(CC) $(CFLAGS) $(CPPFLAGS) -c "$<" -o "$@"


test: CFLAGS += -DRUN_TEST
test: clean kernel disk.img
	qemu-system-x86_64 -kernel kernel -serial stdio -m 32M $(QEMU_OPT)

run:kernel disk.img
	qemu-system-x86_64 -kernel $< $(QEMU_OPT)

debug: CFLAGS += $(DEBUG_FLAGS) -DRUN_TEST
debug: CXXFLAGS += $(DEBUG_FLAGS)
debug:kernel kernel.sym
	gdb -q -x debug.gdb

debug_test: CFLAGS += $(DEBUG_FLAGS) -DRUN_TEST
debug_test: debug

clean:
	$(RM) kernel $(asmobj) $(gasmobj) $(cobj) $(deps) fd.iso kernel.sym
	$(RM) -r isodir

ifneq ($(MAKECMDGOALS),clean)
-include $(deps)
endif