Makefile

TOOLPATH 	:= $(HOME)/opt/cross/bin/
PREFIX 		:= $(TOOLPATH)i386-elf-

AS			:= nasm
CC			:= $(PREFIX)g++
LD			:= $(PREFIX)ld

AS_FLAGS		:= -f elf
CC_FLAGS		:= -ffreestanding -m32 -masm=intel -Wall -Wextra -Wpedantic -Wno-unused-parameter -mno-red-zone -std=c++20 -fno-exceptions -fno-ident -fno-asynchronous-unwind-tables
LD_FLAGS		:= -T linker.ld

BIN				= bin
SRC				= src
RES				= res

BOOT_OUT		= $(BIN)/boot.bin
KERN_OUT		= $(BIN)/kernel.bin


CC_DIR 			= $(SRC)
CC_INCLUDE		= $(SRC)/include
AS_DIR			= $(SRC)
BL_DIR			= $(SRC)/boot
OBJ_DIR			= $(BIN)/obj
BINRES_DIR		= $(BIN)/res

CC_FILES_IN		= $(wildcard $(CC_DIR)/*.cpp)
CC_FILES_OUT	= $(patsubst $(CC_DIR)/%.cpp, $(OBJ_DIR)/%.o, $(CC_FILES_IN))

AS_FILES_IN		= $(wildcard $(AS_DIR)/*.asm)
AS_FILES_OUT	= $(patsubst $(AS_DIR)/%.asm, $(OBJ_DIR)/%.o, $(AS_FILES_IN))

BL_FILES_IN		= $(wildcard $(BL_DIR)/*.asm)
BL_FILES_OUT	= $(patsubst $(BL_DIR)/%.asm, $(OBJ_DIR)/%.bin, $(BL_FILES_IN))

MESH_FILES		= $(wildcard $(RES)/*.obj)
REENCODED_MESHES= $(patsubst $(RES)/%.obj, $(BINRES_DIR)/%.binmesh, $(MESH_FILES))
BMP_FILES		= $(wildcard $(RES)/*.bmp)
REENCODED_BMPS  = $(patsubst $(RES)/%.bmp, $(BINRES_DIR)/%.binbmp, $(BMP_FILES))
EMBED_FILES		= $(REENCODED_MESHES) $(REENCODED_BMPS)
EMBED_FILES_OUT = $(patsubst $(BINRES_DIR)/%, $(BINRES_DIR)/%.o, $(EMBED_FILES))

QEMU_FLAGS 		= -m 32M -monitor stdio -serial file:log/output.log

ifeq ($(DEBUG), 1)
	AS_FLAGS 	:= $(AS_FLAGS) -g
	CC_FLAGS	:= $(CC_FLAGS) -O1 -g
	LD_FLAGS	:= $(LD_FLAGS) -g
	QEMU_FLAGS	:= $(QEMU_FLAGS) -d int,cpu_reset -no-reboot -s -S
else
	CC_FLAGS	:= $(CC_FLAGS) -O3 -s
	LD_FLAGS	:= $(LD_FLAGS) -s
endif

# -g flag enables debug symbols
# -s strips all unecessary shit

$(OBJ_DIR):
	@mkdir -p $(OBJ_DIR)

$(BINRES_DIR):
	@mkdir -p $(BINRES_DIR)

$(OBJ_DIR)/%.o: $(CC_DIR)/%.cpp $(OBJ_DIR)
	@echo "Compiling" $<
	@$(CC) $(CC_FLAGS) -I$(CC_INCLUDE) -c $< -o $@

$(OBJ_DIR)/%.o: $(AS_DIR)/%.asm $(OBJ_DIR)
	@echo "Assembling" $<
	@$(AS) $(AS_FLAGS) $< -o $@

$(OBJ_DIR)/%.bin: $(BL_DIR)/%.asm $(OBJ_DIR)
	@echo "Assembling raw" $<
	@$(AS) -f bin $< -o $@

$(BINRES_DIR)/%.o: $(BINRES_DIR)/% $(BINRES_DIR)
	@echo "Copying resource" $<
	@$(PREFIX)objcopy -I binary -O elf32-i386 -B i386 $< $@
	@$(PREFIX)objcopy -I binary -O elf32-i386 -B i386 $< $@ \
		--redefine-sym _binary_$(subst /,_,$(subst .,_,$(patsubst %.o,%,$@)))_start=_res_$(subst .,_,$(patsubst $(BINRES_DIR)/%,%,$<))_start \
		--redefine-sym _binary_$(subst /,_,$(subst .,_,$(patsubst %.o,%,$@)))_end=_res_$(subst .,_,$(patsubst $(BINRES_DIR)/%,%,$<))_end \
		--redefine-sym _binary_$(subst /,_,$(subst .,_,$(patsubst %.o,%,$@)))_size=_res_$(subst .,_,$(patsubst $(BINRES_DIR)/%,%,$<))_size

$(BINRES_DIR)/%.binmesh: $(RES)/%.obj $(BINRES_DIR)
	@echo "Reencoding" $< "to" $@
	@$(RES)/obj_to_binmesh $< $@

$(BINRES_DIR)/%.binbmp: $(RES)/%.bmp $(BINRES_DIR)
	@echo "Reencoding" $< "to" $@
	@$(RES)/bmp_to_binbmp $< $@

build: $(BL_FILES_OUT) $(CC_FILES_OUT) $(AS_FILES_OUT) $(EMBED_FILES_OUT)
	@echo "Linking" $(KERN_OUT)
	@$(LD) $(LD_FLAGS) -o $(KERN_OUT) $(AS_FILES_OUT) $(CC_FILES_OUT) $(EMBED_FILES_OUT)
	@echo "Stupid concatenation hack" $(BOOT_OUT)
	@cat $(BL_FILES_OUT) $(KERN_OUT) > $(BOOT_OUT)
	@echo "Done, size in bytes:"
	@stat -c%s $(BOOT_OUT)

emulate:
	@mkdir -p log
	qemu-system-x86_64 -drive file=$(BOOT_OUT),format=raw,index=0,media=disk $(QEMU_FLAGS)

disassemble:
	objdump -m i8086 -M intel -b binary -D $(BOOT_OUT)

dump:
	hd $(BOOT_OUT)

analyse: build
	du -ha -d 3 bin

clean:
	@rm -fr $(BIN)

all: clean build emulate

docker:
	@echo "Creating build context..."
	@# "Why not just use a `.dockerignore` instead of this?
	@# 	That would lead to local files (copies of binutils/gcc/gnu-efi sources, build artifacts, etc.)
	@#	  being copied into the build context, which wastes disk space in the Docker cache
	@#	  and leads to more cache invalidation.
	@#	By copying only required files into an otherwise-empty build directory, we have greater control
	@#	  over what gets handed over to the Docker build system.
	@mkdir -p .docker-build
	@rm -fr .docker-build/*
	@# Add any other required materials to this line
	@cp -r linker.ld Makefile src res .docker-build/
	@echo "Building..."
	@cd .docker-build && docker build -f ../Dockerfile . -o ../bin
	@echo "Cleaning up..."
	@rm -r .docker-build
	@echo -e "Done!\nOutput files have been written to ./bin/"