Wrong results from Matlab Function in Real Time

Hello, I'm using "MATLAB Function" (the one that generates code) in a real-time environment model(Quarc). The output of the function though doesn't match the correct output. i.e it's not what it should be. The function is shown at the bottom. If I run the function manually with an input of 1100 for example my output should be a 5x1 element = [65 65 4 76 4]. However in real-time execution I get [65 65 137 128 4]. Why? How can I fix this?

Best regards, Remus

function y = fcn(u)
%#codegen
M_prewrap = u;
M = M_prewrap;
message = [0 0 0 0 0];
message(1) = 65;
message(2) = 65;
check_sum = 0;
i=1;
%for i=1:length(u)
   M_binary = dec2bin(M,16);
   byte1 = bin2dec(M_binary(1:8));
   byte2 = bin2dec(M_binary(9:16));
   message(2*i+1) = byte1;
   message(2*i+2) = byte2;
   check_sum = check_sum + sum(M_binary=='1');
%end

message(end) = check_sum;
y = [message];

[Walter Roberson]

What is your input? '1100' ? 1100 decimal? 12 decimal?