# gbos - Game Boy Color Unix-flavored microkernel (scaffold)
# Toolchain: RGBDS (rgbasm/rgblink/rgbfix)

ROM      := gbos.gb
BUILD    := build
SRCS     := $(wildcard src/*.asm)
OBJS     := $(patsubst src/%.asm,$(BUILD)/%.o,$(SRCS))

ASFLAGS  := -I include -Wall
# MBC5 + RAM + battery; -r 3 = 32 KiB cart RAM (bump for more task banks)
FIXFLAGS := -v -C -m MBC5+RAM+BATTERY -r 4 -p 0xFF -t GBOS

.PHONY: all clean run

all: $(ROM)

$(BUILD)/%.o: src/%.asm | $(BUILD)
	rgbasm $(ASFLAGS) -o $@ $<

# Userland C programs (usr/): compiled with SDCC into ROM-bank blobs under
# $(BUILD)/usr and INCBIN'd by programs.asm
PROGS  := chello echo true false uname pid cat wc head args \
          ls save rm sh ps kill spin blk mkdir count ptest necho \
          wget chat netd ping nslookup dhcp irc uptime
CBLOBS := $(patsubst %,$(BUILD)/usr/%.bin,$(PROGS))
$(BUILD)/programs.o: $(CBLOBS)

# C programs also depend on the shared libc sources
$(CBLOBS): usr/libc.c usr/gbos.h

$(BUILD)/usr/%.bin: usr/%.c usr/crt0.s usr/libc.s usr/build.sh
	sh usr/build.sh $< $@

$(ROM): $(OBJS)
	rgblink -m $(BUILD)/gbos.map -n $(BUILD)/gbos.sym -o $@ $(OBJS)
	rgbfix $(FIXFLAGS) $@

$(BUILD):
	mkdir -p $(BUILD)

clean:
	rm -rf $(BUILD) $(ROM)

# convenience: run in an emulator if one is on PATH
run: $(ROM)
	@which sameboy >/dev/null 2>&1 && sameboy $(ROM) || \
	 which bgb >/dev/null 2>&1 && bgb $(ROM) || \
	 echo "no emulator found (sameboy/bgb)"