Package: std_logic_1164
- File: std_logic_1164.vhdl
Types
| Name | Type | Description |
|---|---|---|
| std_ulogic | ('U', -- Uninitialized, this is also the default value. 'X', -- Unknown / conflict value (forcing level). '0', -- 0 (forcing level). '1', -- 1 (forcing level). 'Z', -- High impedance. 'W', -- Unknown / conflict (weak level). 'L', -- 0 (weak level). 'H', -- 1 (weak level). ) |
|
| std_ulogic_vector | array (natural range <>) of std_ulogic | Vector of logic state. |
| std_logic_vector | array (natural range <>) of std_logic | Vector of std_logic. |
Functions
- resolved (s : std_ulogic_vector) return std_ulogic
Description
Resolution function.
If S is empty, returns 'Z'.
If S has one element, return the element.
Otherwise, 'U' is the strongest.
then 'X'
then '0' and '1'
then 'W'
then 'H' and 'L'
then 'Z'.
- to_bit (s : std_ulogic;
xmap : bit := '0') return bit
Description
Conversion functions.
The result range (for vectors) is S'Length - 1 downto 0.
XMAP is return for values not in '0', '1', 'L', 'H'.
- to_bitvector (s : std_logic_vector;
xmap : bit := '0') return bit_vector
- to_bitvector (s : std_ulogic_vector;
xmap : bit := '0') return bit_vector
- to_stdulogic (b : bit) return std_ulogic
- to_stdlogicvector (b : bit_vector) return std_logic_vector
- to_stdlogicvector (s : std_ulogic_vector) return std_logic_vector
- to_stdulogicvector (b : bit_vector) return std_ulogic_vector
- to_stdulogicvector (s : std_logic_vector) return std_ulogic_vector
- to_X01 (s : std_logic_vector) return std_logic_vector
Description
Normalization.
The result range (for vectors) is 1 to S'Length.
- to_X01 (s : std_ulogic_vector) return std_ulogic_vector
- to_X01 (s : std_ulogic) return X01
- to_X01 (b : bit_vector) return std_logic_vector
- to_X01 (b : bit_vector) return std_ulogic_vector
- to_X01 (b : bit) return X01
- to_X01Z (s : std_logic_vector) return std_logic_vector
- to_X01Z (s : std_ulogic_vector) return std_ulogic_vector
- to_X01Z (s : std_ulogic) return X01Z
- to_X01Z (b : bit_vector) return std_logic_vector
- to_X01Z (b : bit_vector) return std_ulogic_vector
- to_X01Z (b : bit) return X01Z
- to_UX01 (s : std_logic_vector) return std_logic_vector
- to_UX01 (s : std_ulogic_vector) return std_ulogic_vector
- to_UX01 (s : std_ulogic) return UX01
- to_UX01 (b : bit_vector) return std_logic_vector
- to_UX01 (b : bit_vector) return std_ulogic_vector
- to_UX01 (b : bit) return UX01
- rising_edge (signal s : std_ulogic) return boolean
Description
Edge detection.
An edge is detected in case of event on s, and X01 normalized value
rises from 0 to 1 or falls from 1 to 0.
- falling_edge (signal s : std_ulogic) return boolean
- is_X (s : std_ulogic_vector) return boolean
Description
Test for unknown. Only 0, 1, L and H are known values.
- is_X (s : std_logic_vector) return boolean
- is_X (s : std_ulogic) return boolean