SHELL = /bin/sh
.SUFFIXES: # Disable implicit rules.

CC        = avr-gcc
CFLAGS   := $(CFLAGS) -mmcu=avr128da28 -Os -std=gnu99 -Wall -Wextra -Wpedantic -Wno-pointer-arith
CPPFLAGS := $(CPPFLAGS) -Iinclude -DNDEBUG

ASFLAGS  := $(ASFLAGS) -mmcu=avr128da28 -Os
LDFLAGS  := $(LDFLAGS) -nostdlib -flto
LDLIBS   := $(LDLIBS)  -lgcc

# Find source files
SRC := $(shell find src/ -name '*.[cS]' -print)
DIR := $($(sort $(foreach f,$(SRC),$(dir $f))):%=obj/%) bin/

# Configure common functions for logging
msg-as    = $(info	[AS]	$(1))
msg-cc    = $(info	[CC]	$(1))
msg-clean = $(info	[CLEAN]	$(1))
msg-ld    = $(info	[LD]	$(1))
msg-tar   = $(info	[TAR]	$(1))
msg-xxd   = $(info	[XXD]	$(1))

# Set Q to @ to silence commands being printed, if --no-silent has not been set
ifeq (0, $(words $(findstring --no-silent,$(MAKEFLAGS))))
Q=@
endif

.PHONY: $(DIR) all clean
all: bin/a.out bin/a.hex
clean:; $(Q)-$(RM) -rv bin/ obj/

# Links object files to a binary
bin/a.out: $(SRC:%=obj/%.o)
	$(Q)$(call msg-ld,$@)
	$(Q)$(CC) $(LDFLAGS) $(LDLIBS) -o $@ $^

# Links object files to a stripped binary
bin/a.hex: $(SRC:%=obj/%.o)
	$(Q)$(call msg-ld,$@)
	$(Q)$(CC) -s $(LDFLAGS) $(LDLIBS) -o $@ $^

# Assembles preprocessed assembly into object files
obj/%.S.d: %.S;  $Q$(CC) -MM $(ASFLAGS) $(CPPFLAGS) -MF $@ $<
obj/%.S.o: %.S
	$(Q)$(call msg-as,$@)
	$(Q)$(CC) -c $(ASFLAGS) $(CPPFLAGS) -o $@ $<

# Compiles C sources into object files
obj/%.c.d: %.c;  $Q$(CC) -MM $(CFLAGS) $(CPPFLAGS) -MF $@ $<
obj/%.c.o: %.c %.c.d
	$(Q)mkdir $(@D)
	$(Q)$(call msg-cc,$@)
	$(Q)$(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<

# Include dependencies, ignoring any errors that may occur when doing so.
ifeq (0, $(words $(findstring $(MAKECMDGOALS), clean)))
# -include $(SRC:%=obj/%.d)
endif