Output samples are alway zero

Hi,
    I am trying to port Madlib on PalmOS using Codewarrior.So far I have
been able to compile and run Madlib using
CW. The function 'mad_frame_decode' dosnt return any error meaning the data
is being decoded properly( isnt it).
 
But after that when the 'mad_synth_frame' is called it doesnt fills  the pcm
samples.Can I figure out a way using which I can find whether 
these function are working properly or not.I debugged the 'synth_full' and
'synth_half' function but didnt for ne thing out of it.
 
Regards,
Swapnil