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library ieee;
use ieee.std_logic_1164.all;
package pkg is
type sulv_vector is array (natural range <>) of std_ulogic_vector;
subtype NULL_RANGE is natural range 0 downto 1;
constant NULL_SULV : std_ulogic_vector(NULL_RANGE) := (others => '0');
constant NULL_SULV_VECTOR : sulv_vector(NULL_RANGE)(NULL_RANGE) := (others => NULL_SULV);
function repeat(
val : std_ulogic;
n : natural
) return std_ulogic_vector;
function repeat(
val : std_ulogic_vector;
m : natural
) return sulv_vector;
function align_left(
vec : std_ulogic_vector;
len : positive;
pad : std_ulogic := '0'
) return std_ulogic_vector;
end package;
package body pkg is
function repeat(
val : std_ulogic;
n : natural)
return std_ulogic_vector
is
begin
if n = 0 then
return NULL_SULV;
else
return (n - 1 downto 0 => val);
end if;
end function;
function repeat(
val : std_ulogic_vector;
m : natural
) return sulv_vector
is
begin
if m = 0 then
return NULL_SULV_VECTOR;
else
return (m - 1 downto 0 => val);
end if;
end function;
-- function repeat(
-- val : std_ulogic_vector;
-- m : natural
-- ) return sulv_vector
-- is
-- constant result : sulv_vector(m downto 1)(val'range) := (others => val);
-- begin
-- return result;
-- end function;
function align_left(
vec : std_ulogic_vector;
len : positive;
pad : std_ulogic := '0')
return std_ulogic_vector
is
constant diff : integer := len - vec'length;
alias v : std_ulogic_vector(vec'length - 1 downto 0) is vec;
variable result : std_ulogic_vector(len - 1 downto 0);
begin
assert diff >= 0
report "align_left: cannot align larger vector into smaller vector"
severity failure;
result := (v, repeat(pad, diff));
return result;
end function;
end package body;
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