I'm interested in learning about what's under the hood, or what's hidden from you by an IDE, by which I mean, compiler, linker, makefiles - that type of thing. I have a few specific, if potentially misguided questions about what I think I should be doing…

How to use GNU ARM binutils for cortex-M4? When I try to compile with -mcpu=cortex-M4 -march=armV7e-m I get 'bad value in switches'.