A bug in the benchmark program...

[JacksonGL]

I know this is a performance benchmark. But there is probably a bug here.

if (sixbits[3] >= 0x40) {
	decode64.length -= 1;  // no side effect
	if (sixbits[2] >= 0x40) {
		decode64.length -= 1; // no side effect
	}
}

decode64 holds a primitive string value. Decreasing its length property has no side effect: it won't throw away the last character.