> sprintf "%o" (0o123456 >>> 3);; val it : string = "12345" > sprintf "%o" (0o123456 >>> 9);; val it : string = "123" > sprintf "%o" (0o123456 >>> 12);; val it : string = "12" > sprintf "%o" (0o123456 >>> 15);; val it : string = "1"
3bitでとりうる値は0-7で8進数1桁。
4bitでとりうる値は0-15で16進数1桁。