C is no compromise. If you never programmed in assembly (or C, C++, python, perl) then your assembly code is not going to be faster than your C code for anything more useful then a countdown loop, for at least a few years. By then, even ARM might be superscalar and out of order, so you will need to start optimizing your super fast code all over again.

If you do want to learn ARM assembly (it is useful for a lot of things, just not for speed), you need the ARM ARM, since that is the standard text.