20:10:49jcowanClearly boxing double floats only makes sense on 64-bit systems
20:11:26moon-childyes; on 64-bit x86, immediates generally only go up to 32 bits
20:11:54moon-childso you pessimise the type tests by putting the tag so high
20:13:00jcowanhttps://wingolog.org/archives/2011/05/18/value-representation-in-javascript-implementations is not 100% clear, but I don't have time atm to do better