A numeric_std compatible replacement for std_logic_arith and std_logic_unsigned.
ALL STD_LOGIC_VECTORS are considered UNSIGNED. If SIGNED operation is needed, due to very specific and INTENDED behavior, it should be used the SIGNED type on NUMERIC_STD.
RANGE_T: record that includes "low" and "high" fields. Used to expand the ranges on VHDL.
USE:
signal|variable myrange : range_t := ( high => <integer>, low => <integer> );
STD_LOGIC_ARRAY: An unconstrained array of unconstrained std_logic_vector. Some tools take a problem with it.
USE:
signal|variable myarray : std_logic_array(y downto 0)(x downto 0) := ( 0 => <vector0>, 1 => <vector1>, others => <vector> );
| Function | Input Types |
|---|---|
| TO_INTEGER(input) | STD_LOGIC_VECTOR |
| TO_STD_LOGIC_VECTOR(input) | INTEGER,SIGNED,UNSIGEND |
| TO_UNSIGNED(input) | STD_LOGIC_VECTOR,SIGNED |
| TO_SIGNED(input) | UNSIGNED |
It covers following operators:
| Operator | LEFT | RIGHT | RESULT | Description |
|---|---|---|---|---|
| + , - , * , / | STD_LOGIC_VECTOR | STD_LOGIC_VECTOR, INTEGER, UNSIGNED | STD_LOGIC_VECTOR | Arithmetic operator |
| INTEGER | STD_LOGIC_VECTOR | STD_LOGIC_VECTOR | ||
| UNSIGNED | STD_LOGIC_VECTOR | STD_LOGIC_VECTOR | ||
| > , < , >= , <= , = , /= | STD_LOGIC_VECTOR | INTEGER | BOOLEAN | Comparator operator |
| INTEGER | STD_LOGIC_VECTOR | BOOLEAN | ||
| rol , ror | STD_LOGIC_VECTOR | STD_LOGIC_VECTOR | STD_LOGIC_VECTOR | Rotation, getting the bit and placing back to begining. |
| Function | Use | Description |
|---|---|---|
| size_of | size_of(number,) | Return the minimum number of bits that an integer requires to be represented. If a word size is provided, the minimum number of words to represent that number. |
| index_of | index_of(vector) | Return the relative position of that register inside a larger register. (i.e. for byte, the byte number of that slice) |
| rebase | rebase(vector) | Returns an std_logic_vector starting with 0 and little endian. |
| range_of | range_of(vector) | Returns a range_t containing vector'high and vector'low |
| get_slice | get_slice(vector,word_size,index) | Returns a smaller vector (size of word_size) a portion of input vector corresponding to a word number (example: byte0 is 7..0, byte1 is 15..8) |
| set_slice | set_slice(vector,word,index) | Retruns a vector replacing a portion of vector corresponding to a word number (example: byte0 is 7..0, byte1 is 15..8). Works best ir size_of(vector) is a multiple of size_of(word) |
| to_range | to_range(vector) | Returns a range_t containing vector'high and vector'low |
| index_of_1 | index_of_1(vector) | Returns the index of highest '1' bit. |
| index_of_0 | index_of_0(vector) | Returns the index of highest '0' bit. |
| all_1 | all_1(input) | Returns an "all ones" vector sized input-1 downto 0 |
| all_0 | all_0(input) | Returns an "all zeroes" vector sized input-1 downto 0 |