make: add support for building a host version

Makefile

@@ -1,27 +1,21 @@
+TARGET ?= host
+TARGET := $(filter host stm32f0,${TARGET})
+
+ifeq (${TARGET},)
+$(error No support available for the target)
+endif
+
 BUILD ?= build
-PREFIX ?= arm-none-eabi
+BUILD := $(addsuffix /${TARGET},${BUILD})
 
 all: $(BUILD)/tbm
 
-LDSCRIPT = support/stm32f0-discovery.ld
+-include scripts/Makefile.${TARGET}
 
 CFLAGS += -Iinclude
 CFLAGS += -Wall -Wundef -Wextra -Wshadow -Wimplicit-function-declaration
 CFLAGS += -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes
 CFLAGS += -fno-common --function-sections -fdata-sections
-LDFLAGS += -static -nostartfiles
-LDFLAGS += -Wl,--gc-sections
-LIBS += -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group
-
-# Set up libopencm3.
-OPENCM3_DIR ?= libopencm3
-OPENCM3_LIBNAME = opencm3_stm32f0
-CFLAGS += -I$(OPENCM3_DIR)/include
-CFLAGS += -DSTM32F0 -msoft-float -mthumb -mcpu=cortex-m0
-LDFLAGS += -L$(OPENCM3_DIR)/lib
-LIBS += -l$(OPENCM3_LIBNAME)
-
-STLINK_PORT ?= :4242
 
 obj-y += source/main.o
 obj-y += source/shell.o
@@ -45,29 +39,15 @@ clean:
 	@echo "CLEAN"
 	@rm -rf $(BUILD)
 
-$(OPENCM3_DIR)/lib/lib$(OPENCM3_LIBNAME).a:
-	@if [ ! -e libopencm3/.git ]; then \
-		git submodule init; \
-		git submodule update; \
-	fi
-	@$(MAKE) -C $(OPENCM3_DIR)
-
 # Rule to compile C source code.
 $(BUILD)/%.o: %.c
 	@echo "CC $<"
 	@mkdir -p $(dir $@)
 	@$(CC) -c $< -o $@ $(CFLAGS) -MT $@ -MMD -MP -MF $(@:.o=.d)
 
-$(BUILD)/tbm: $(obj) $(LDSCRIPT) $(OPENCM3_DIR)/lib/lib$(OPENCM3_LIBNAME).a
+$(BUILD)/tbm: $(obj) $(LDSCRIPT)
 	@echo "LD $@"
 	@mkdir -p $(dir $@)
 	@$(LD) -o $@ $(CFLAGS) $(LDFLAGS) -T $(LDSCRIPT) $(obj) $(LIBS)
 
-run: $(BUILD)/tbm
-	@echo "GDB $<"
-	@$(GDB) --batch \
-		-ex 'target extended-remote $(STLINK_PORT)' \
-		-x flash.scr \
-		$<
-
-.PHONY: clean run
+.PHONY: clean

scripts/Makefile.stm32f0

@@ -0,0 +1,35 @@
+PREFIX ?= arm-none-eabi
+
+LDSCRIPT = support/stm32f0-discovery.ld
+
+LDFLAGS += -static -nostartfiles
+LDFLAGS += -Wl,--gc-sections
+LIBS += -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group
+
+# Set up libopencm3.
+OPENCM3_DIR ?= libopencm3
+OPENCM3_LIBNAME = opencm3_stm32f0
+CFLAGS += -I$(OPENCM3_DIR)/include
+CFLAGS += -DSTM32F0 -msoft-float -mthumb -mcpu=cortex-m0
+LDFLAGS += -L$(OPENCM3_DIR)/lib
+LIBS += -l$(OPENCM3_LIBNAME)
+
+STLINK_PORT ?= :4242
+
+$(OPENCM3_DIR)/lib/lib$(OPENCM3_LIBNAME).a:
+	@if [ ! -e libopencm3/.git ]; then \
+		git submodule init; \
+		git submodule update; \
+	fi
+	@$(MAKE) -C $(OPENCM3_DIR)
+
+$(BUILD)/tbm: $(OPENCM3_DIR)/lib/lib$(OPENCM3_LIBNAME).a
+
+run: $(BUILD)/tbm
+	@echo "GDB $<"
+	@$(GDB) --batch \
+		-ex 'target extended-remote $(STLINK_PORT)' \
+		-x flash.scr \
+		$<
+
+.PHONY: run