TARGET = firmware

DEBUG = 1
OPT = -O0

BUILD_DIR = build

SRC_DIRS := $(shell find src -type d)
CC_SOURCES = $(foreach folder, $(SRC_DIRS), $(wildcard $(folder)/*.cc))
C_SOURCES = $(foreach folder, $(SRC_DIRS), $(wildcard $(folder)/*.c))
ASM_SOURCES = $(foreach folder, $(SRC_DIRS), $(wildcard $(folder)/*.s))

PREFIX = arm-none-eabi-
CC = $(PREFIX)gcc
CXX = $(PREFIX)g++
AS = $(PREFIX)gcc -x assembler-with-cpp
CP = $(PREFIX)objcopy
SZ = $(PREFIX)size

HEX = $(CP) -O ihex
BIN = $(CP) -O binary -S
 
CPU = -mcpu=cortex-m0plus
MCU = $(CPU) -mthumb $(FPU) $(FLOAT-ABI)

C_DEFS = -DSTM32G031xx
LDSCRIPT = src/platform/stm32g0xx/STM32G031Y8YX_FLASH.ld

ASFLAGS = $(MCU) $(AS_DEFS) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
CFLAGS = $(MCU) $(C_DEFS) $(addprefix -I,$(SRC_DIRS)) $(OPT) -Wall -fdata-sections -ffunction-sections

ifeq ($(DEBUG), 1)
CFLAGS += -ggdb3
endif

CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"

LIBS = -lc -lm -lnosys
LIBDIR =
LDFLAGS = $(MCU) -specs=nano.specs -T$(LDSCRIPT) $(LIBDIR) $(LIBS) -Wl,-Map=$(BUILD_DIR)/$(TARGET).map,--cref -Wl,--gc-sections

all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin

OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(CC_SOURCES:.cc=.o)))
vpath %.cc $(sort $(dir $(CC_SOURCES)))

OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
vpath %.c $(sort $(dir $(C_SOURCES)))

OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.s=.o)))
vpath %.s $(sort $(dir $(ASM_SOURCES)))

$(BUILD_DIR)/%.o: %.cc Makefile | $(BUILD_DIR) 
	$(CXX) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.cc=.lst)) $< -o $@

$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR) 
	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@

$(BUILD_DIR)/%.o: %.s Makefile | $(BUILD_DIR)
	$(AS) -c $(CFLAGS) $< -o $@

$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) | Makefile
	$(CXX) $(OBJECTS) $(LDFLAGS) -o $@
	$(SZ) $@

$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
	$(HEX) $< $@

$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
	$(BIN) $< $@

$(BUILD_DIR):
	mkdir $@

clean:
	-rm -fR $(BUILD_DIR)

-include $(wildcard $(BUILD_DIR)/*.d)