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Diffstat (limited to 'libraries/ieee/std_logic_1164.vhdl')
| -rw-r--r-- | libraries/ieee/std_logic_1164.vhdl | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/libraries/ieee/std_logic_1164.vhdl b/libraries/ieee/std_logic_1164.vhdl new file mode 100644 index 000000000..c53113be9 --- /dev/null +++ b/libraries/ieee/std_logic_1164.vhdl @@ -0,0 +1,175 @@ +-- -------------------------------------------------------------------- +-- +-- 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; --V93 + 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; + +-- ----------------------------------------------------------------------- +-- Note : The declaration and implementation of the "xnor" function is +-- specifically commented until at which time the VHDL language has been +-- officially adopted as containing such a function. At such a point, +-- the following comments may be removed along with this notice without +-- further "official" ballotting of this std_logic_1164 package. It is +-- the intent of this effort to provide such a function once it becomes +-- available in the VHDL standard. +-- ----------------------------------------------------------------------- + FUNCTION "xnor" ( l, r : std_logic_vector ) RETURN std_logic_vector; --V93 + FUNCTION "xnor" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;--V93 + + 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; |