bitcoin/secp256k1 — pull request #124 by sipa (2014-11-30 18:46:21+00:00)
Title: Enforce and use r != b for field multiplication

This was suggested by Peter Dettman, results in a 1.7% speedup (when compiled with --field=64bit --enable-endomorphism CFLAGS=-O3), and could simplify assembly implementations.