porting glibc

[Somshekar. C. Kadam - CTD, Chennai.]

hi,
 i am newbie ,i need to port glibc for new platform ,
 i am working on porting linux ,
i need to implement systemcall ,on linux side i ahve set up the table for
system call i am not getting how glibc will  give the systemcall number , so
that it indexes into systemcall table entry and corresponding function  is
invoked 
any idea pls help 
thanks in advance 
somshekar