const math/rand.rngMask

3 uses

	math/rand (current package)
		rand.go#L363: 	return int64(runtime_rand() & rngMask)
		rng.go#L18: 	rngMask  = rngMax - 1
		rng.go#L234: 	return int64(rng.Uint64() & rngMask)