Demonstrate assembly source files

my-project/Makefile

@@ -4,6 +4,7 @@ BUILD_DIR = bin
 SHARED_DIR = ../my-common-code
 CFILES = my-project.c
 CFILES += api.c
+AFILES += api-asm.S
 
 # TODO - you will need to edit these two lines!
 DEVICE=stm32f407vgt6

my-project/my-project.c

@@ -1,6 +1,9 @@
 #include "api.h"
+#include "api-asm.h"
 
 int main(void) {
 	/* add your own code */
-	return my_func(3);
+	uint32_t rev = 0xaabbccdd;
+	rev = rev_bytes(rev);
+	return my_func(rev);
 }

rules.mk

@@ -56,6 +56,7 @@ OPENCM3_INC = $(OPENCM3_DIR)/include
 INCLUDES += $(patsubst %,-I%, . $(OPENCM3_INC) )
 
 OBJS = $(CFILES:%.c=$(BUILD_DIR)/%.o)
+OBJS += $(AFILES:%.S=$(BUILD_DIR)/%.o)
 GENERATED_BINS = $(PROJECT).elf $(PROJECT).bin $(PROJECT).map $(PROJECT).list $(PROJECT).lss
 
 TGT_CPPFLAGS += -MD
@@ -75,6 +76,8 @@ TGT_CXXFLAGS += -fno-common
 TGT_CXXFLAGS += -ffunction-sections -fdata-sections
 TGT_CXXFLAGS += -Wextra -Wshadow -Wredundant-decls  -Weffc++
 
+TGT_ASFLAGS += $(OPT) $(ARCH_FLAGS) -ggdb3
+
 TGT_LDFLAGS += -T$(LDSCRIPT) -L$(OPENCM3_DIR)/lib -nostartfiles
 TGT_LDFLAGS += $(ARCH_FLAGS)
 TGT_LDFLAGS += -specs=nano.specs
@@ -95,7 +98,7 @@ LDLIBS += -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group
 
 # Burn in legacy hell fortran modula pascal yacc idontevenwat
 .SUFFIXES:
-.SUFFIXES: .c .h .o .cxx .elf .bin .list .lss
+.SUFFIXES: .c .S .h .o .cxx .elf .bin .list .lss
 
 # Bad make, never *ever* try to get a file out of source control by yourself.
 %: %,v
@@ -129,6 +132,11 @@ $(BUILD_DIR)/%.o: %.cxx
 	@mkdir -p $(dir $@)
 	$(Q)$(CC) $(TGT_CXXFLAGS) $(CXXFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<
 
+$(BUILD_DIR)/%.o: %.S
+	@printf "  AS\t$<\n"
+	@mkdir -p $(dir $@)
+	$(Q)$(CC) $(TGT_ASFLAGS) $(ASFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<
+
 $(PROJECT).elf: $(OBJS) $(LDSCRIPT) $(LIBDEPS)
 	@printf "  LD\t$@\n"
 	$(Q)$(LD) $(TGT_LDFLAGS) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $@