[U-Boot] what does it mean when "SOBJS" refers to a C source file?

perusing the Makefiles, pretty straightforward but, on occasion, i run into something like this (from arch/arm/cpu/armv7/omap-common/Makefile):

... snip ... SOBJS := reset.o

COBJS := timer.o COBJS += utils.o ... snip ...

the thing is, all of the above are .c files, including reset.c. is there something deliberate about using SOBJS to refer to an object file whose source file isn't actually assembler? just curious.

rday