A collection of commonly used math routines, so I don't have to write them again. Implementations in C, C++, Rust, and Python (though not so much in Python as it already has a pretty good set of libraries).

SIN, COS, SQRT, RSQRT & FLOOR(LOG2(x)) in fixed-point representation, targetting tiny 32-bit platforms. Notably, C++ STL is not required.