What is the role of .s files in a C project?

Question

I am working with an ARM Cortex M3 chip (STM32F2) and ST provides a \"standard peripheral library\". It has some useful .c and .h files. It also has .s files.

What i

Answer 1

They usually contain assembly code. The assembler turns them into object files which are later linked by the linker with the main stuff. But I imagine it does depend on the compiler, toolchain etc.