The COUNTERS library contains the most common used counters and consists of the following 6 generic components :

buNar	:	N-bit binary up counter with asynchronous reset
bdNsr	:	N-bit binary down counter with synchronous reset
budNlr	:	N-bit binary up-down counter with syncronous load and asynchronous reset
guNar	:	N-bit gray up counter with asynchronous reset
gdNsr	:	N-bit gray down counter with synchronous reset
gudNlr	:	N-bit gray up-down counter with syncronous load and asynchronous reset

The COUNTERs library can be verified with this testbench : test_counters