TOOLSET = $(WINAVR)/20070525
#TOOLSET = $(WINAVR)/20060421
TOOL_DIR = $(TOOLSET)/bin
UTILS_DIR = $(TOOLSET)/utils/bin

## General Flags
MCU = atmega8

F_CPU =7372800
PROJECT =TRx150-RRP
PROJ_SRCTOP= .\
MODULES=

TARGET = $(PROJECT).elf

OUTDIR = ./release
OBJDIR = $(OUTDIR)/obj
LSTDIR = $(OUTDIR)/lst
DEPDIR = $(OUTDIR)/dep

CC = $(TOOL_DIR)/avr-gcc.exe
OBJCOPY = $(TOOL_DIR)/avr-objcopy.exe
OBJDUMP = $(TOOL_DIR)/avr-objdump.exe
SIZE = $(TOOL_DIR)/avr-size.exe
RM = $(UTILS_DIR)/rm
## Options common to compile, link and assembly rules
COMMON = -mmcu=$(MCU)

## Compile options common for all C compilation units.
CFLAGS = $(COMMON)
CFLAGS += -Wall -gdwarf-2
CFLAGS += -DF_CPU=$(F_CPU)UL
CFLAGS += -Os
CFLAGS += -fsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
CFLAGS += -MD -MP -MT $(OBJDIR)/$(*F).o -MF $(DEPDIR)/$(@F).d
CFLAGS += -ffunction-sections
CFLAGS += -fdata-sections

## Assembly specific flags
ASMFLAGS = $(COMMON)
ASMFLAGS += $(CFLAGS)
ASMFLAGS += -x assembler-with-cpp -Wa,-gdwarf2

## Linker flags
LDFLAGS = $(COMMON)
LDFLAGS += -Wl,-Map=$(LSTDIR)/$(PROJECT).map
LDFLAGS += -Wl,-T,./TRx150.ld
LDFLAGS += -Wl,--defsym,BootLoader=0x1800
LDFLAGS += -Wl,--gc-sections
LDFLAGS += -Wl,-relax
## Link libm library - asm math-functions
LDFLAGS += -Wl,-lm

## Intel Hex file production flags
HEX_FLASH_FLAGS = -R .eeprom

HEX_EEPROM_FLAGS = -j .eeprom
HEX_EEPROM_FLAGS += --set-section-flags=.eeprom="alloc,load"
HEX_EEPROM_FLAGS += --change-section-lma .eeprom=0 --no-change-warnings


## Source files
SRCDIRS = . $(addprefix $(PROJ_SRCTOP)/,$(MODULES))
CSRC    = $(wildcard $(addsuffix /*.c,$(SRCDIRS)))
CPPSRC    = $(wildcard $(addsuffix /*.cpp,$(SRCDIRS)))
ASRC    = $(wildcard $(addsuffix /*.S,$(SRCDIRS)))

## Objects that must be built in order to link
OBJ = $(addprefix $(OBJDIR)/,$(notdir $(CSRC:.c=.o) $(CPPSRC:.cpp=.o) $(ASRC:.S=.o) ))
LST    = $(addprefix $(LSTDIR)/,$(notdir $(CSRC:.c=.lst) $(CPPSRC:.cpp=.lst) $(ASRC:.S=.lst) ))

## Objects explicitly added by the user
LINKONLYOBJECTS =

## Build
all: create_dirs $(TARGET) $(PROJECT).hex $(PROJECT).eep $(PROJECT).lss size
    -@$(UTILS_DIR)/cp $(OUTDIR)/$(TARGET) $(TARGET)

# all obj files depend on makefile because of makefile contain
#  some compiler's switches (optimisation, debug options, etc..)
$(OBJ) : makefile

## Compile
$(OBJDIR)/%.o: %.c
    $(CC) $(INCLUDES) $(CFLAGS) -Wa,-ahlmsd=$(LSTDIR)/$(notdir $(<:.c=.lst)) -c  $< -o $@
$(OBJDIR)/%.o: %.cpp
    $(CC) $(INCLUDES) $(CFLAGS) -Wa,-ahlmsd=$(LSTDIR)/$(notdir $(<:.cpp=.lst)) -c  $< -o $@
$(OBJDIR)/%.o: %.S
    $(CC) $(INCLUDES) $(ASMFLAGS) -c  $< -o $@
$(OBJDIR)/%.o: %.s
    $(CC) $(INCLUDES) $(ASMFLAGS) -c  $< -o $@

##Link
$(TARGET): $(OBJ) TRx150.ld
     $(CC) $(LDFLAGS) $(OBJ) $(LINKONLYOBJECTS) $(LIBDIRS) $(LIBS) -o $(OUTDIR)/$(TARGET)

%.hex: $(TARGET)
    $(OBJCOPY) -O ihex $(HEX_FLASH_FLAGS)  $(OUTDIR)/$< $(OUTDIR)/$@

%.eep: $(TARGET)
    -$(OBJCOPY) -O ihex $(HEX_EEPROM_FLAGS) $(OUTDIR)/$< $(OUTDIR)/$@ || exit 0

%.lss: $(TARGET)
    $(OBJDUMP) -h -S $(OUTDIR)/$< > $(LSTDIR)/$@

size: ${TARGET}
    @echo
    @$(SIZE) -C --mcu=${MCU} $(OUTDIR)/${TARGET}

## Clean target
.PHONY: clean
clean:
    -@$(UTILS_DIR)/rm -rf $(OUTDIR) $(TARGET)
create_dirs:
    -@$(UTILS_DIR)/mkdir -p $(OBJDIR) $(DEPDIR) $(LSTDIR)

...

    CFLAGS += -ffunction-sections -fdata-sections
    LDFLAGS += -Wl,--gc-sections
    LDFLAGS += -Wl,--relax