| Type | Defined In IEEE Package | SubType Of | Contains Values |
|---|---|---|---|
| std_ulogic | std_logic_1164 | N/A |
Same values as std_logic Does not contain predefined resolution functions |
| X01 | std_logic_1164 | std_ulogic | X, 0, 1 |
| X01Z | std_logic_1164 | std_ulogic | X, 0, 1, Z |
| UX01 | std_logic_1164 | std_ulogic | U, X, 0, 1 |
| UX01Z | std_logic_1164 | std_ulogic | U, X, 0, Z |