conv_unsigned() - std_logic_arith

These functions convert the arg argument to an unsigned value with size bits.

The function provided by the std_logic_arith library can't convert a std_logic_vector to an integer because it is impossible to determine if it represents an unsigned or signed value. Functions that do this are included in the std_logic_unsigned and std_logic_signed libraries.

Syntax

function conv_unsigned(arg: integer, size: integer) return unsigned;
function conv_unsigned(arg: unsigned, size: integer) return unsigned;
function conv_unsigned(arg: signed, size: integer) return unsigned;
function conv_unsigned(arg: std_ulogic, size: integer) return unsigned;

Example

signal u1, u2 : unsigned (3 downto 0);
signal s1 : signed (3 downto 0);
signal i1, i2 : integer;
...
s1 <= "0101";
i1 <= 13;
wait for 10 ns;
u1 <= conv_unsigned(s1, 4);   -- = "0101" = 5
u2 <= conv_unsigned(i1, 4);   -- = "1101" = 13

Output / Return Value

Limitations

Alternatives / See Also

Reference

https://www.cs.sfu.ca/~ggbaker/reference/std_logic/arith/conv_unsigned.html