-- --------------------------------------------------------------------
--
-- Title : std_logic_1164 multi-value logic system
-- Library : This package shall be compiled into a library
-- : symbolically named IEEE.
-- :
-- Developers: IEEE model standards group (par 1164)
-- Purpose : This packages defines a standard for designers
-- : to use in describing the interconnection data types
-- : used in vhdl modeling.
-- :
-- Limitation: The logic system defined in this package may
-- : be insufficient for modeling switched transistors,
-- : since such a requirement is out of the scope of this
-- : effort. Furthermore, mathematics, primitives,
-- : timing standards, etc. are considered orthogonal
-- : issues as it relates to this package and are therefore
-- : beyond the scope of this effort.
-- :
-- Note : No declarations or definitions shall be included in,
-- : or excluded from this package. The "package declaration"
-- : defines the types, subtypes and declarations of
-- : std_logic_1164. The std_logic_1164 package body shall be
-- : considered the formal definition of the semantics of
-- : this package. Tool developers may choose to implement
-- : the package body in the most efficient manner available
-- : to them.
-- :
-- --------------------------------------------------------------------
-- modification history :
-- --------------------------------------------------------------------
-- version | mod. date:|
-- v4.200 | 01/02/92 |
-- --------------------------------------------------------------------
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_ulogic for use with the resolution function
-------------------------------------------------------------------
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;
-------------------------------------------------------------------
-- unconstrained array of std_logic for use in declaring signal arrays
-------------------------------------------------------------------
TYPE std_logic_vector IS ARRAY ( NATURAL RANGE <>) OF std_logic;
-------------------------------------------------------------------
-- common subtypes
-------------------------------------------------------------------
SUBTYPE X01 IS resolved std_ulogic RANGE 'X' TO '1'; -- ('X','0','1')
SUBTYPE X01Z IS resolved std_ulogic RANGE 'X' TO 'Z'; -- ('X','0','1','Z')
SUBTYPE UX01 IS resolved std_ulogic RANGE 'U' TO '1'; -- ('U','X','0','1')
SUBTYPE UX01Z IS resolved std_ulogic RANGE 'U' TO 'Z'; -- ('U','X','0','1','Z')
-------------------------------------------------------------------
-- overloaded logical operators
-------------------------------------------------------------------
FUNCTION "and" ( l : std_ulogic; r : std_ulogic ) RETURN UX01;
FUNCTION "nand" ( l : std_ulogic; r : std_ulogic ) RETURN UX01;
FUNCTION "or" ( l : std_ulogic; r : std_ulogic ) RETURN UX01;
FUNCTION "nor" ( l : std_ulogic; r : std_ulogic ) RETURN UX01;
FUNCTION "xor" ( l : std_ulogic; r : std_ulogic ) RETURN UX01;
function "xnor" ( l : std_ulogic; r : std_ulogic ) return ux01;
FUNCTION "not" ( l : std_ulogic ) RETURN UX01;
-------------------------------------------------------------------
-- vectorized overloaded logical operators
-------------------------------------------------------------------
FUNCTION "and" ( l, r : std_logic_vector ) RETURN std_logic_vector;
FUNCTION "and" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION "nand" ( l, r : std_logic_vector ) RETURN std_logic_vector;
FUNCTION "nand" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION "or" ( l, r : std_logic_vector ) RETURN std_logic_vector;
FUNCTION "or" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION "nor" ( l, r : std_logic_vector ) RETURN std_logic_vector;
FUNCTION "nor" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION "xor" ( l, r : std_logic_vector ) RETURN std_logic_vector;
FUNCTION "xor" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
function "xnor" ( l, r : std_logic_vector ) return std_logic_vector;
function "xnor" ( l, r : std_ulogic_vector ) return std_ulogic_vector;
FUNCTION "not" ( l : std_logic_vector ) RETURN std_logic_vector;
FUNCTION "not" ( l : std_ulogic_vector ) RETURN std_ulogic_vector;
-------------------------------------------------------------------
-- conversion functions
-------------------------------------------------------------------
FUNCTION To_bit ( s : std_ulogic; xmap : BIT := '0') RETURN BIT;
FUNCTION To_bitvector ( s : std_logic_vector ; xmap : BIT := '0') RETURN BIT_VECTOR;
FUNCTION To_bitvector ( s : std_ulogic_vector; xmap : BIT := '0') RETURN BIT_VECTOR;
FUNCTION To_StdULogic ( b : BIT ) RETURN std_ulogic;
FUNCTION To_StdLogicVector ( b : BIT_VECTOR ) RETURN std_logic_vector;
FUNCTION To_StdLogicVector ( s : std_ulogic_vector ) RETURN std_logic_vector;
FUNCTION To_StdULogicVector ( b : BIT_VECTOR ) RETURN std_ulogic_vector;
FUNCTION To_StdULogicVector ( s : std_logic_vector ) RETURN std_ulogic_vector;
-------------------------------------------------------------------
-- strength strippers and type convertors
-------------------------------------------------------------------
FUNCTION To_X01 ( s : std_logic_vector ) RETURN std_logic_vector;
FUNCTION To_X01 ( s : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION To_X01 ( s : std_ulogic ) RETURN X01;
FUNCTION To_X01 ( b : BIT_VECTOR ) RETURN std_logic_vector;
FUNCTION To_X01 ( b : BIT_VECTOR ) RETURN std_ulogic_vector;
FUNCTION To_X01 ( b : BIT ) RETURN X01;
FUNCTION To_X01Z ( s : std_logic_vector ) RETURN std_logic_vector;
FUNCTION To_X01Z ( s : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION To_X01Z ( s : std_ulogic ) RETURN X01Z;
FUNCTION To_X01Z ( b : BIT_VECTOR ) RETURN std_logic_vector;
FUNCTION To_X01Z ( b : BIT_VECTOR ) RETURN std_ulogic_vector;
FUNCTION To_X01Z ( b : BIT ) RETURN X01Z;
FUNCTION To_UX01 ( s : std_logic_vector ) RETURN std_logic_vector;
FUNCTION To_UX01 ( s : std_ulogic_vector ) RETURN std_ulogic_vector;
FUNCTION To_UX01 ( s : std_ulogic ) RETURN UX01;
FUNCTION To_UX01 ( b : BIT_VECTOR ) RETURN std_logic_vector;
FUNCTION To_UX01 ( b : BIT_VECTOR ) RETURN std_ulogic_vector;
FUNCTION To_UX01 ( b : BIT ) RETURN UX01;
-------------------------------------------------------------------
-- edge detection
-------------------------------------------------------------------
FUNCTION rising_edge (SIGNAL s : std_ulogic) RETURN BOOLEAN;
FUNCTION falling_edge (SIGNAL s : std_ulogic) RETURN BOOLEAN;
-------------------------------------------------------------------
-- object contains an unknown
-------------------------------------------------------------------
FUNCTION Is_X ( s : std_ulogic_vector ) RETURN BOOLEAN;
FUNCTION Is_X ( s : std_logic_vector ) RETURN BOOLEAN;
FUNCTION Is_X ( s : std_ulogic ) RETURN BOOLEAN;
END std_logic_1164;
PACKAGE BODY std_logic_1164 IS
-------------------------------------------------------------------
-- local types
-------------------------------------------------------------------
TYPE stdlogic_1d IS ARRAY (std_ulogic) OF std_ulogic;
TYPE stdlogic_table IS ARRAY(std_ulogic, std_ulogic) OF std_ulogic;
-------------------------------------------------------------------
-- resolution function
-------------------------------------------------------------------
CONSTANT resolution_table : stdlogic_table := (
-- ---------------------------------------------------------
-- | U X 0 1 Z W L H - | |
-- ---------------------------------------------------------
( 'U', 'U', 'U', 'U', 'U', 'U', 'U', 'U', 'U' ), -- | U |
( 'U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X' ), -- | X |
( 'U', 'X', '0', 'X', '0', '0', '0', '0', 'X' ), -- | 0 |
( 'U', 'X', 'X', '1', '1', '1', '1', '1', 'X' ), -- | 1 |
( 'U', 'X', '0', '1', 'Z', 'W', 'L', 'H', 'X' ), -- | Z |
( 'U', 'X', '0', '1', 'W', 'W', 'W', 'W', 'X' ), -- | W |
( 'U', 'X', '0', '1', 'L', 'W', 'L', 'W', 'X' ), -- | L |
( 'U', 'X', '0', '1', 'H', 'W', 'W', 'H', 'X' ), -- | H |
( 'U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X' ) -- | - |
);
FUNCTION resolved ( s : std_ulogic_vector ) RETURN std_ulogic IS
VARIABLE result : std_ulogic := 'Z'; -- weakest state default
BEGIN
-- the test for a single driver is essential otherwise the
-- loop would return 'X' for a single driver of '-' and that
-- would conflict with the value of a single driver unresolved
-- signal.
IF (s'LENGTH = 1) THEN RETURN s(s'LOW);
ELSE
FOR i IN s'RANGE LOOP
result := resolution_table(result, s(i));
END LOOP;
END IF;
RETURN result;
END resolved;
-------------------------------------------------------------------
-- tables for logical operations
-------------------------------------------------------------------
-- truth table for "and" function
CONSTANT and_table : stdlogic_table := (
-- ----------------------------------------------------
-- | U X 0 1 Z W L H - | |
-- ----------------------------------------------------
( 'U', 'U', '0', 'U', 'U', 'U', '0', 'U', 'U' ), -- | U |
( 'U', 'X', '0', 'X', 'X', 'X', '0', 'X', 'X' ), -- | X |
( '0', '0', '0', '0', '0', '0', '0', '0', '0' ), -- | 0 |
( 'U', 'X', '0', '1', 'X', 'X', '0', '1', 'X' ), -- | 1 |
( 'U', 'X', '0', 'X', 'X', 'X', '0', 'X', 'X' ), -- | Z |
( 'U', 'X', '0', 'X', 'X', 'X', '0', 'X', 'X' ), -- | W |
( '0', '0', '0', '0', '0', '0', '0', '0', '0' ), -- | L |
( 'U', 'X', '0', '1', 'X', 'X', '0', '1', 'X' ), -- | H |
( 'U', 'X', '0', 'X', 'X', 'X', '0', 'X', 'X' ) -- | - |
);
-- truth table for "or" function
CONSTANT or_table : stdlogic_table := (
-- ----------------------------------------------------
-- | U X 0 1 Z W L H - | |
-- ----------------------------------------------------
( 'U', 'U', 'U', '1', 'U', 'U', 'U', '1', 'U' ), -- | U |
( 'U', 'X', 'X', '1', 'X', 'X', 'X', '1', 'X' ), -- | X |
( 'U', 'X', '0', '1', 'X', 'X', '0', '1', 'X' ), -- | 0 |
( '1', '1', '1', '1', '1', '1', '1', '1', '1' ), -- | 1 |
( 'U', 'X', 'X', '1', 'X', 'X', 'X', '1', 'X' ), -- | Z |
( 'U', 'X', 'X', '1', 'X', 'X', 'X', '1', 'X' ), -- | W |
( 'U', 'X', '0', '1', 'X', 'X', '0', '1', 'X' ), -- | L |
( '1', '1', '1', '1', '1', '1', '1', '1', '1' ), -- | H |
( 'U', 'X', 'X', '1', 'X', 'X', 'X', '1', 'X' ) -- | - |
);
-- truth table for "xor" function
CONSTANT xor_table : stdlogic_table := (
-- ----------------------------------------------------
-- | U X 0 1 Z W L H - | |
-- ----------------------------------------------------
( 'U', 'U', 'U', 'U', 'U', 'U', 'U', 'U', 'U' ), -- | U |
( 'U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X' ), -- | X |
( 'U', 'X', '0', '1', 'X', 'X', '0', '1', 'X' ), -- | 0 |
( 'U', 'X', '1', '0', 'X', 'X', '1', '0', 'X' ), -- | 1 |
( 'U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X' ), -- | Z |
( 'U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X' ), -- | W |
( 'U', 'X', '0', '1', 'X', 'X', '0', '1', 'X' ), -- | L |
( 'U', 'X', '1', '0', 'X', 'X', '1', '0', 'X' ), -- | H |
( 'U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X' ) -- | - |
);
-- truth table for "not" function
CONSTANT not_table: stdlogic_1d :=
-- -------------------------------------------------
-- | U X 0 1 Z W L H - |
-- -------------------------------------------------
( 'U', 'X', '1', '0', 'X', 'X', '1', '0', 'X' );
-------------------------------------------------------------------
-- overloaded logical operators ( with optimizing hints )
-------------------------------------------------------------------
FUNCTION "and" ( l : std_ulogic; r : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (and_table(l, r));
END "and";
FUNCTION "nand" ( l : std_ulogic; r : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (not_table ( and_table(l, r)));
END "nand";
FUNCTION "or" ( l : std_ulogic; r : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (or_table(l, r));
END "or";
FUNCTION "nor" ( l : std_ulogic; r : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (not_table ( or_table( l, r )));
END "nor";
FUNCTION "xor" ( l : std_ulogic; r : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (xor_table(l, r));
END "xor";
function "xnor" ( l : std_ulogic; r : std_ulogic ) return ux01 is
begin
return not_table(xor_table(l, r));
end "xnor";
FUNCTION "not" ( l : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (not_table(l));
END "not";
-------------------------------------------------------------------
-- and
-------------------------------------------------------------------
FUNCTION "and" ( l,r : std_logic_vector ) RETURN std_logic_vector IS
ALIAS lv : std_logic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_logic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_logic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'and' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := and_table (lv(i), rv(i));
END LOOP;
END IF;
RETURN result;
END "and";
---------------------------------------------------------------------
FUNCTION "and" ( l,r : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS lv : std_ulogic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_ulogic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_ulogic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'and' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := and_table (lv(i), rv(i));
END LOOP;
END IF;
RETURN result;
END "and";
-------------------------------------------------------------------
-- nand
-------------------------------------------------------------------
FUNCTION "nand" ( l,r : std_logic_vector ) RETURN std_logic_vector IS
ALIAS lv : std_logic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_logic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_logic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'nand' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := not_table(and_table (lv(i), rv(i)));
END LOOP;
END IF;
RETURN result;
END "nand";
---------------------------------------------------------------------
FUNCTION "nand" ( l,r : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS lv : std_ulogic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_ulogic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_ulogic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'nand' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := not_table(and_table (lv(i), rv(i)));
END LOOP;
END IF;
RETURN result;
END "nand";
-------------------------------------------------------------------
-- or
-------------------------------------------------------------------
FUNCTION "or" ( l,r : std_logic_vector ) RETURN std_logic_vector IS
ALIAS lv : std_logic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_logic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_logic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'or' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := or_table (lv(i), rv(i));
END LOOP;
END IF;
RETURN result;
END "or";
---------------------------------------------------------------------
FUNCTION "or" ( l,r : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS lv : std_ulogic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_ulogic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_ulogic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'or' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := or_table (lv(i), rv(i));
END LOOP;
END IF;
RETURN result;
END "or";
-------------------------------------------------------------------
-- nor
-------------------------------------------------------------------
FUNCTION "nor" ( l,r : std_logic_vector ) RETURN std_logic_vector IS
ALIAS lv : std_logic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_logic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_logic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'nor' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := not_table(or_table (lv(i), rv(i)));
END LOOP;
END IF;
RETURN result;
END "nor";
---------------------------------------------------------------------
FUNCTION "nor" ( l,r : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS lv : std_ulogic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_ulogic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_ulogic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'nor' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := not_table(or_table (lv(i), rv(i)));
END LOOP;
END IF;
RETURN result;
END "nor";
---------------------------------------------------------------------
-- xor
-------------------------------------------------------------------
FUNCTION "xor" ( l,r : std_logic_vector ) RETURN std_logic_vector IS
ALIAS lv : std_logic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_logic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_logic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'xor' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := xor_table (lv(i), rv(i));
END LOOP;
END IF;
RETURN result;
END "xor";
---------------------------------------------------------------------
FUNCTION "xor" ( l,r : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS lv : std_ulogic_vector ( 1 TO l'LENGTH ) IS l;
ALIAS rv : std_ulogic_vector ( 1 TO r'LENGTH ) IS r;
VARIABLE result : std_ulogic_vector ( 1 TO l'LENGTH );
BEGIN
IF ( l'LENGTH /= r'LENGTH ) THEN
ASSERT FALSE
REPORT "arguments of overloaded 'xor' operator are not of the same length"
SEVERITY FAILURE;
ELSE
FOR i IN result'RANGE LOOP
result(i) := xor_table (lv(i), rv(i));
END LOOP;
END IF;
RETURN result;
END "xor";
-------------------------------------------------------------------
-- xnor
-------------------------------------------------------------------
function "xnor" ( l,r : std_logic_vector ) return std_logic_vector is
alias lv : std_logic_vector ( 1 to l'length ) is l;
alias rv : std_logic_vector ( 1 to r'length ) is r;
variable result : std_logic_vector ( 1 to l'length );
begin
if ( l'length /= r'length ) then
assert false
report "arguments of overloaded 'xnor' operator are not of the same length"
severity failure;
else
for i in result'range loop
result(i) := not_table(xor_table (lv(i), rv(i)));
end loop;
end if;
return result;
end "xnor";
---------------------------------------------------------------------
function "xnor" ( l,r : std_ulogic_vector ) return std_ulogic_vector is
alias lv : std_ulogic_vector ( 1 to l'length ) is l;
alias rv : std_ulogic_vector ( 1 to r'length ) is r;
variable result : std_ulogic_vector ( 1 to l'length );
begin
if ( l'length /= r'length ) then
assert false
report "arguments of overloaded 'xnor' operator are not of the same length"
severity failure;
else
for i in result'range loop
result(i) := not_table(xor_table (lv(i), rv(i)));
end loop;
end if;
return result;
end "xnor";
-------------------------------------------------------------------
-- not
-------------------------------------------------------------------
FUNCTION "not" ( l : std_logic_vector ) RETURN std_logic_vector IS
ALIAS lv : std_logic_vector ( 1 TO l'LENGTH ) IS l;
VARIABLE result : std_logic_vector ( 1 TO l'LENGTH ) := (OTHERS => 'X');
BEGIN
FOR i IN result'RANGE LOOP
result(i) := not_table( lv(i) );
END LOOP;
RETURN result;
END;
---------------------------------------------------------------------
FUNCTION "not" ( l : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS lv : std_ulogic_vector ( 1 TO l'LENGTH ) IS l;
VARIABLE result : std_ulogic_vector ( 1 TO l'LENGTH ) := (OTHERS => 'X');
BEGIN
FOR i IN result'RANGE LOOP
result(i) := not_table( lv(i) );
END LOOP;
RETURN result;
END;
-------------------------------------------------------------------
-- conversion tables
-------------------------------------------------------------------
TYPE logic_x01_table IS ARRAY (std_ulogic'LOW TO std_ulogic'HIGH) OF X01;
TYPE logic_x01z_table IS ARRAY (std_ulogic'LOW TO std_ulogic'HIGH) OF X01Z;
TYPE logic_ux01_table IS ARRAY (std_ulogic'LOW TO std_ulogic'HIGH) OF UX01;
----------------------------------------------------------
-- table name : cvt_to_x01
--
-- parameters :
-- in : std_ulogic -- some logic value
-- returns : x01 -- state value of logic value
-- purpose : to convert state-strength to state only
--
-- example : if (cvt_to_x01 (input_signal) = '1' ) then ...
--
----------------------------------------------------------
CONSTANT cvt_to_x01 : logic_x01_table := (
'X', -- 'U'
'X', -- 'X'
'0', -- '0'
'1', -- '1'
'X', -- 'Z'
'X', -- 'W'
'0', -- 'L'
'1', -- 'H'
'X' -- '-'
);
----------------------------------------------------------
-- table name : cvt_to_x01z
--
-- parameters :
-- in : std_ulogic -- some logic value
-- returns : x01z -- state value of logic value
-- purpose : to convert state-strength to state only
--
-- example : if (cvt_to_x01z (input_signal) = '1' ) then ...
--
----------------------------------------------------------
CONSTANT cvt_to_x01z : logic_x01z_table := (
'X', -- 'U'
'X', -- 'X'
'0', -- '0'
'1', -- '1'
'Z', -- 'Z'
'X', -- 'W'
'0', -- 'L'
'1', -- 'H'
'X' -- '-'
);
----------------------------------------------------------
-- table name : cvt_to_ux01
--
-- parameters :
-- in : std_ulogic -- some logic value
-- returns : ux01 -- state value of logic value
-- purpose : to convert state-strength to state only
--
-- example : if (cvt_to_ux01 (input_signal) = '1' ) then ...
--
----------------------------------------------------------
CONSTANT cvt_to_ux01 : logic_ux01_table := (
'U', -- 'U'
'X', -- 'X'
'0', -- '0'
'1', -- '1'
'X', -- 'Z'
'X', -- 'W'
'0', -- 'L'
'1', -- 'H'
'X' -- '-'
);
-------------------------------------------------------------------
-- conversion functions
-------------------------------------------------------------------
FUNCTION To_bit ( s : std_ulogic; xmap : BIT := '0') RETURN BIT IS
BEGIN
CASE s IS
WHEN '0' | 'L' => RETURN ('0');
WHEN '1' | 'H' => RETURN ('1');
WHEN OTHERS => RETURN xmap;
END CASE;
END;
--------------------------------------------------------------------
FUNCTION To_bitvector ( s : std_logic_vector ; xmap : BIT := '0') RETURN BIT_VECTOR IS
ALIAS sv : std_logic_vector ( s'LENGTH-1 DOWNTO 0 ) IS s;
VARIABLE result : BIT_VECTOR ( s'LENGTH-1 DOWNTO 0 );
BEGIN
FOR i IN result'RANGE LOOP
CASE sv(i) IS
WHEN '0' | 'L' => result(i) := '0';
WHEN '1' | 'H' => result(i) := '1';
WHEN OTHERS => result(i) := xmap;
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_bitvector ( s : std_ulogic_vector; xmap : BIT := '0') RETURN BIT_VECTOR IS
ALIAS sv : std_ulogic_vector ( s'LENGTH-1 DOWNTO 0 ) IS s;
VARIABLE result : BIT_VECTOR ( s'LENGTH-1 DOWNTO 0 );
BEGIN
FOR i IN result'RANGE LOOP
CASE sv(i) IS
WHEN '0' | 'L' => result(i) := '0';
WHEN '1' | 'H' => result(i) := '1';
WHEN OTHERS => result(i) := xmap;
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_StdULogic ( b : BIT ) RETURN std_ulogic IS
BEGIN
CASE b IS
WHEN '0' => RETURN '0';
WHEN '1' => RETURN '1';
END CASE;
END;
--------------------------------------------------------------------
FUNCTION To_StdLogicVector ( b : BIT_VECTOR ) RETURN std_logic_vector IS
ALIAS bv : BIT_VECTOR ( b'LENGTH-1 DOWNTO 0 ) IS b;
VARIABLE result : std_logic_vector ( b'LENGTH-1 DOWNTO 0 );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_StdLogicVector ( s : std_ulogic_vector ) RETURN std_logic_vector IS
ALIAS sv : std_ulogic_vector ( s'LENGTH-1 DOWNTO 0 ) IS s;
VARIABLE result : std_logic_vector ( s'LENGTH-1 DOWNTO 0 );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := sv(i);
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_StdULogicVector ( b : BIT_VECTOR ) RETURN std_ulogic_vector IS
ALIAS bv : BIT_VECTOR ( b'LENGTH-1 DOWNTO 0 ) IS b;
VARIABLE result : std_ulogic_vector ( b'LENGTH-1 DOWNTO 0 );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_StdULogicVector ( s : std_logic_vector ) RETURN std_ulogic_vector IS
ALIAS sv : std_logic_vector ( s'LENGTH-1 DOWNTO 0 ) IS s;
VARIABLE result : std_ulogic_vector ( s'LENGTH-1 DOWNTO 0 );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := sv(i);
END LOOP;
RETURN result;
END;
-------------------------------------------------------------------
-- strength strippers and type convertors
-------------------------------------------------------------------
-- to_x01
-------------------------------------------------------------------
FUNCTION To_X01 ( s : std_logic_vector ) RETURN std_logic_vector IS
ALIAS sv : std_logic_vector ( 1 TO s'LENGTH ) IS s;
VARIABLE result : std_logic_vector ( 1 TO s'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := cvt_to_x01 (sv(i));
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01 ( s : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS sv : std_ulogic_vector ( 1 TO s'LENGTH ) IS s;
VARIABLE result : std_ulogic_vector ( 1 TO s'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := cvt_to_x01 (sv(i));
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01 ( s : std_ulogic ) RETURN X01 IS
BEGIN
RETURN (cvt_to_x01(s));
END;
--------------------------------------------------------------------
FUNCTION To_X01 ( b : BIT_VECTOR ) RETURN std_logic_vector IS
ALIAS bv : BIT_VECTOR ( 1 TO b'LENGTH ) IS b;
VARIABLE result : std_logic_vector ( 1 TO b'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01 ( b : BIT_VECTOR ) RETURN std_ulogic_vector IS
ALIAS bv : BIT_VECTOR ( 1 TO b'LENGTH ) IS b;
VARIABLE result : std_ulogic_vector ( 1 TO b'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01 ( b : BIT ) RETURN X01 IS
BEGIN
CASE b IS
WHEN '0' => RETURN('0');
WHEN '1' => RETURN('1');
END CASE;
END;
--------------------------------------------------------------------
-- to_x01z
-------------------------------------------------------------------
FUNCTION To_X01Z ( s : std_logic_vector ) RETURN std_logic_vector IS
ALIAS sv : std_logic_vector ( 1 TO s'LENGTH ) IS s;
VARIABLE result : std_logic_vector ( 1 TO s'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := cvt_to_x01z (sv(i));
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01Z ( s : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS sv : std_ulogic_vector ( 1 TO s'LENGTH ) IS s;
VARIABLE result : std_ulogic_vector ( 1 TO s'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := cvt_to_x01z (sv(i));
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01Z ( s : std_ulogic ) RETURN X01Z IS
BEGIN
RETURN (cvt_to_x01z(s));
END;
--------------------------------------------------------------------
FUNCTION To_X01Z ( b : BIT_VECTOR ) RETURN std_logic_vector IS
ALIAS bv : BIT_VECTOR ( 1 TO b'LENGTH ) IS b;
VARIABLE result : std_logic_vector ( 1 TO b'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01Z ( b : BIT_VECTOR ) RETURN std_ulogic_vector IS
ALIAS bv : BIT_VECTOR ( 1 TO b'LENGTH ) IS b;
VARIABLE result : std_ulogic_vector ( 1 TO b'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_X01Z ( b : BIT ) RETURN X01Z IS
BEGIN
CASE b IS
WHEN '0' => RETURN('0');
WHEN '1' => RETURN('1');
END CASE;
END;
--------------------------------------------------------------------
-- to_ux01
-------------------------------------------------------------------
FUNCTION To_UX01 ( s : std_logic_vector ) RETURN std_logic_vector IS
ALIAS sv : std_logic_vector ( 1 TO s'LENGTH ) IS s;
VARIABLE result : std_logic_vector ( 1 TO s'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := cvt_to_ux01 (sv(i));
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_UX01 ( s : std_ulogic_vector ) RETURN std_ulogic_vector IS
ALIAS sv : std_ulogic_vector ( 1 TO s'LENGTH ) IS s;
VARIABLE result : std_ulogic_vector ( 1 TO s'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
result(i) := cvt_to_ux01 (sv(i));
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_UX01 ( s : std_ulogic ) RETURN UX01 IS
BEGIN
RETURN (cvt_to_ux01(s));
END;
--------------------------------------------------------------------
FUNCTION To_UX01 ( b : BIT_VECTOR ) RETURN std_logic_vector IS
ALIAS bv : BIT_VECTOR ( 1 TO b'LENGTH ) IS b;
VARIABLE result : std_logic_vector ( 1 TO b'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_UX01 ( b : BIT_VECTOR ) RETURN std_ulogic_vector IS
ALIAS bv : BIT_VECTOR ( 1 TO b'LENGTH ) IS b;
VARIABLE result : std_ulogic_vector ( 1 TO b'LENGTH );
BEGIN
FOR i IN result'RANGE LOOP
CASE bv(i) IS
WHEN '0' => result(i) := '0';
WHEN '1' => result(i) := '1';
END CASE;
END LOOP;
RETURN result;
END;
--------------------------------------------------------------------
FUNCTION To_UX01 ( b : BIT ) RETURN UX01 IS
BEGIN
CASE b IS
WHEN '0' => RETURN('0');
WHEN '1' => RETURN('1');
END CASE;
END;
-------------------------------------------------------------------
-- edge detection
-------------------------------------------------------------------
FUNCTION rising_edge (SIGNAL s : std_ulogic) RETURN BOOLEAN IS
BEGIN
RETURN (s'EVENT AND (To_X01(s) = '1') AND
(To_X01(s'LAST_VALUE) = '0'));
END;
FUNCTION falling_edge (SIGNAL s : std_ulogic) RETURN BOOLEAN IS
BEGIN
RETURN (s'EVENT AND (To_X01(s) = '0') AND
(To_X01(s'LAST_VALUE) = '1'));
END;
-------------------------------------------------------------------
-- object contains an unknown
-------------------------------------------------------------------
FUNCTION Is_X ( s : std_ulogic_vector ) RETURN BOOLEAN IS
BEGIN
FOR i IN s'RANGE LOOP
CASE s(i) IS
WHEN 'U' | 'X' | 'Z' | 'W' | '-' => RETURN TRUE;
WHEN OTHERS => NULL;
END CASE;
END LOOP;
RETURN FALSE;
END;
--------------------------------------------------------------------
FUNCTION Is_X ( s : std_logic_vector ) RETURN BOOLEAN IS
BEGIN
FOR i IN s'RANGE LOOP
CASE s(i) IS
WHEN 'U' | 'X' | 'Z' | 'W' | '-' => RETURN TRUE;
WHEN OTHERS => NULL;
END CASE;
END LOOP;
RETURN FALSE;
END;
--------------------------------------------------------------------
FUNCTION Is_X ( s : std_ulogic ) RETURN BOOLEAN IS
BEGIN
CASE s IS
WHEN 'U' | 'X' | 'Z' | 'W' | '-' => RETURN TRUE;
WHEN OTHERS => NULL;
END CASE;
RETURN FALSE;
END;
END std_logic_1164;