Makefile

SHELL := /usr/bin/env bash

OUT := out
IMG_SIZE_MB := 16
KERNEL_SECTORS := 80

APP_DIRS := $(sort $(patsubst %/,%,$(dir $(wildcard src/apps/*/Makefile))))
APP_NAMES := $(notdir $(APP_DIRS))
APP_PACKAGES := $(addprefix $(OUT)/apps/,$(addsuffix .app,$(APP_NAMES)))

.PHONY: all apps kernel clean run finish

all: $(OUT)/disk.img finish

apps: $(APP_PACKAGES)

kernel: $(OUT)/kernel.bin

$(OUT):
	mkdir -p $(OUT)

$(OUT)/apps: | $(OUT)
	mkdir -p $(OUT)/apps

$(OUT)/kernel:
	mkdir -p $(OUT)/kernel

$(OUT)/apps/%.app: | $(OUT)/apps
	$(MAKE) -C src/apps/$* OUT_DIR=../../../$(OUT)/apps APP_LINKER=../linker.ld

$(OUT)/boot.bin: boot.asm | $(OUT)
	nasm -f bin boot.asm -o $@

$(OUT)/kernel/kernel_entry.o: kernel_entry.asm | $(OUT)/kernel
	nasm -f elf32 kernel_entry.asm -o $@

$(OUT)/kernel/isr_stubs.o: isr_stubs.asm | $(OUT)/kernel
	nasm -f elf32 isr_stubs.asm -o $@

$(OUT)/kernel.elf: $(OUT)/kernel/kernel_entry.o $(OUT)/kernel/isr_stubs.o
	$(MAKE) -C src/kernel

$(OUT)/kernel.bin: $(OUT)/kernel.elf
	objcopy -O binary $< $@
	@KERNEL_SIZE=$$(wc -c < $@); \
	BUDGET=$$(( $(KERNEL_SECTORS) * 512 )); \
	if [ "$$KERNEL_SIZE" -gt "$$BUDGET" ]; then \
		echo ""; \
		echo "WARNING: kernel.bin is $$KERNEL_SIZE bytes, but boot.asm only loads $$BUDGET bytes ($(KERNEL_SECTORS) sectors)."; \
		echo "         Bump 'mov dh, $(KERNEL_SECTORS)' in boot.asm to cover $$(( (KERNEL_SIZE + 511) / 512 )) sectors."; \
	fi

$(OUT)/mkkfs2: tools/mkkfs2.c | $(OUT)
	gcc -std=c99 -O2 $< -o $@

$(OUT)/disk.img: $(OUT)/boot.bin $(OUT)/kernel.bin $(OUT)/mkkfs2 $(APP_PACKAGES)
	truncate -s "$(IMG_SIZE_MB)M" $@
	dd if=$(OUT)/boot.bin of=$@ conv=notrunc status=none
	dd if=$(OUT)/kernel.bin of=$@ bs=512 seek=1 conv=notrunc status=none
	$(OUT)/mkkfs2 $@ $(APP_PACKAGES)

finish:
	@printf -- "-----\nqemu-system-i386 -drive format=raw,file=$(OUT)/disk.img,if=ide,index=0,media=disk\n-----\n"

clean:
	rm -rf $(OUT)