Why 1164 used in encoder vhdl programming?

VHDL program follows IEEE library. This means that all the data types, commands, keyWords etc. used in a VHDL program are stored in a library called IEEE library. This library will be available in the EDA tool which is executing the VHDL program. 1164 is a package where all the logic gates are defined. This is a sub part of IEEE library. As encoder program requires logic gates, we need to use 1164 package in the code.