About subband synthesis

Hello all,

           I am trying to improve the performance of the MP3 decoder.
       One idea is to improve the subband synthesis.
       In the MAD, the subroutine, synth_full(), process the subband synthesis.
       In this subroutine, it can be found that the data (dct32 output) is accessed sequentially.
       However, the coefficients (synthesis window) is not accessed sequential.
       I am trying to modify the subroutine in order to access the coefficients sequentially.
       My question is that where can i find the document about the flow of the subroutine or suggestion.
       


                                                                      thanks a lot!!
                                                                      Best Regards