[ixp1200] microC compile problem

Hi, We are trying to write a program in microC using the IXP developer's workbench. In the process we used some intrinsic functions from the library provided called ua_get_u8() and ua_get_u16() and included the header file ixp.h. However, we get a compiler error saying function __shr_64 not found . The function does not seem to exist anywhere in the include/ or even in the files and subfolders under the IXP1200/ directory and we haven't yet found a file containing an implementation of it either. Please, does anyone have a fix for this problem ? thanks, Maruti