intialisation of matrix of integers

[mohansriram]

please help me how to initialise a matrix containing integers of order 2x2
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>what is the problem in following program, i could'nt understand:


library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_signed.all;

entity test_12 is
port(a,b,c,d:in integer;e,f,g,h: out std_logic_vector(4 downto 0));

end test_12;

architecture behv of test_12 is
type a11 is array(1 to 2,1 to 2) of std_logic_vector(2 downto 0);
type b11 is array(1 to 2,1 to 2) of std_logic_vector(2 downto 0);
signal sa,sb,sc,sd:signed(3 downto 0);
begin
sa<= conv_signed(a,4);
sb<= conv_signed(b,4);
sc<= conv_signed(c,4);
sd<= conv_signed(d,4);
a11<=((sa,sb),(sc,sd));
process
begin
e:=a1(1,1)+'1';
end process;
end behv;

in this program, it was showing that "conv_signed" is unknown identifier
but conv_signed is predefined function in std_logic_arith library....

please anyone help me in this program