IEEE 1164 Declarations for STD_ULOGIC, STD_LOGIC

PACKAGE std_logic_1164 IS

-- logic state system (unresolved)

type STD_ULOGIC is ( ‘U’, -- Uninitialized

‘X’, -- Forcing Unknown

‘0’, -- Forcing 0

‘1’, -- Forcing 1

‘Z’, -- High Impedance

‘W’, -- Weak Unknown

‘L’, -- Weak 0

‘H’, -- Weak 1

‘-’ -- Don’t Care

);

-- unconstrained array of std_logic

TYPE std_ulogic_vector IS ARRAY (NATURAL RANGE <> ) OF std_ulogic;

-- resolution function

FUNCTION resolved (s : std_ulogic_vector ) return std_ulogic;

-- *** industry standard logic type ***

SUBTYPE std_logic IS resolved std_ulogic;