It's always interesting to review numerical mathematics at this level. If this interests you, you may want to read C Lanczos's book Applied Analysis and Hank W

It's always interesting to review numerical mathematics at this level. If this interests you, you may want to read C Lanczos's book Applied Analysis and Hank Warren's book Hackers Delight as well as the classic MIT HAKMEM report available on the Web. On machines with highly asymmetric architectures it's sometimes worthwhile to use a superoptimizer approach (https://en.wikipedia.org/wiki/Superoptimization https://en.wikipedia.org/wiki/Superoptimization). See the classic paper by Alexia Massalin and the gnu implementation.