(40 . 6)(40 . 9)
1118 -- The very same Word, but its only legal values are 0 and 1.
1119 subtype WBool is Word range 0 .. 1;
1120
1121 -- Word, restricted to Nibble range.
1122 subtype Nibble is Word range 0 .. 16#F#;
1123
1124 -- When we must refer to individual bit positions of a machine word:
1125 subtype WBit_Index is Natural range 0 .. Bitness - 1;
1126