problem with initialising rom and reading data

Hi,

I would like to read binary data from a text file. Perform FIR filtering on the data and store the simulated result values in another text/mif file for further processing in Matlab. I used $readmemb function with verilog code in Quartus II. The following code seems to work.

module test(addr_a,addr_b,clk,q_a,q_b,c);

input [3:0] addr_a,addr_b;

input clk;

output [3:0] q_a,q_b;

output [7:0] c;

reg [7:0] c;

reg [3:0] q_a,q_b;

parameter data_width=4;

parameter addr_width=4;

reg[data_width-1:0] rom[2*addr_width-1:0];

initial

begin

$readmemb("script.txt",rom);

end

always@(posedge clk)

begin

q_a<=rom[addr_a];

q_b<=rom[addr_b];

c<=q_a+q_b;

end

endmodule

But instead if I use the following, my code does not work.

always@(posedge clk)

begin

x[0]<=rom[n];

n<=n+1;

temp<=x[0];

end

I don't want to use the address as input signal. I would like to use a counter to fetch the subsequent addresses. Could someone suggest me how to do that.