# Used to generated .d file that deal with header dependencies
CPPFLAGS = -MMD
AS=nasm
ASFLAGS += -f elf32
#LDFLAGS += -m32 -nostdlib -mkernel -fno-stack-protector
LDFLAGS += -m32 -nostdlib -static -fno-common -fno-use-cxa-atexit -fno-exceptions -fno-non-call-exceptions -fno-weak -fno-rtti -fno-stack-protector
CFLAGS += -m32 -Wall -Wextra -Werror -ffreestanding -fno-exceptions -fno-pie -fno-stack-protector
CXXFLAGS += -m32 -Wall -Wextra -Werror -ffreestanding -fno-exceptions -fno-rtti -fno-pie
DEBUG_FLAGS += -g -Og -DDEBUG -fno-omit-frame-pointer -fno-inline

SUBDIRS := core drivers tests

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

asmsrc=$(wildcard *.asm)
asmobj=$(asmsrc:%.asm=%.o)
csrc=$(shell find $(SUBDIRS) -type f -name "*.c")#   $(wildcard *.c)
cobj=$(csrc:%.c=%.o)
deps = $(csrc:%.c=%.d)

kernel:$(asmobj) $(cobj) linker.ld
	$(CC) -m32  -ffreestanding -nostdlib  $(cobj) $(asmobj) -o $@ -T linker.ld
	objcopy --only-keep-debug $@ $@.sym
	objcopy --strip-debug  $@

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


#https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#x86-Function-Attributes
core/exception_handler.o:core/exception_handler.c
	$(CC) $(CFLAGS) $(CPPFLAGS) -mgeneral-regs-only  -c $< -o $@
core/irq_handler.o:core/irq_handler.c
	$(CC) $(CFLAGS) $(CPPFLAGS) -mgeneral-regs-only  -c $< -o $@

%.o:%.asm
	$(AS) $(ASFLAGS) -o $@ $<

self_test: CFLAGS += -DRUN_TEST -DDEBUG
self_test: clean kernel
	qemu-system-x86_64 -kernel kernel -serial stdio

test:kernel
	qemu-system-x86_64 -kernel $<

debug: CFLAGS += $(DEBUG_FLAGS)
debug: CXXFLAGS += $(DEBUG_FLAGS)
debug:kernel kernel.sym
	qemu-system-x86_64 -s -S -kernel kernel&
	gdb -s kernel.sym -ex "target remote localhost:1234"

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

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