simulation in xilinx blockset and silmulink matlab incorrert ????

[boyzzun]

hi guys, i have project about adaptive filter, i built a model in system generator based on hldcoderlms,but when i start with first tap of filter the result between hdl coder(simulink matlab) and my model (on system generator) is incorrecrt (or i can say wrong), but i dont know why, please help me
PS: if anyone has model system generator of LMS FIR can supprort for me,its verry helpful with me right now