impulse response of CIC filter

hello all , I have a problem when designing CIC filter on matlab here is the code :

    r=64;
    m=1;
    n=3;
    IFL = 0; % Input fraction length
    CIC = mfilt.cicdecim(r,m,n);
    CIC.InputFracLength = IFL;
I use fvtool to check the impulse response

I also used the following code as another check for impulse response (w/o using fvtool):

    x= [1 zeros(1,511-1)];
    d=filter(CIC,x);
    stem(d);
and I got response which is completely different from the first one

what is the problem ? I am intending to use fdhdltool for verilog code o/p after setting teh filter specs on matlab

Regards,