Adding a automatically generated assembly file

Hi.

I tried to add an automatically generated assembly file ended with .s(lowercase) to my project. It cannot be added like .S with ASRC+= . I thought it should be complied to .o first and I tried to add

Compile: create object files from .s files.
$(OBJDIR)/%.o : %.s
@$(ECHO_BLANK)
@echo $(MSG_COMPILING) $<
$(CC) -c $(ALL_CFLAGS) $< -o $@

but it didn’t work. I wanna know how can I add this .s file.
Here is some part of the .s file:

Can you just rename the .s files to .S? AFAIK the only difference is the former aren’t run through the C preprocessor.