Explained purpose of diag_mod <> 0.

libraries/base/diag/src/vhdl/mms_diag_tx_seq.vhd

@@ -133,6 +133,13 @@
 --    diag_step = 2**g_seq_dat_w - diag_mod + g_cnt_incr to verify ok as 
 --    simulated with tb_tb_diag_rx_seq. In this mms_diag_tx_seq g_cnt_incr=1
 --    fixed for diag_tx_seq.
+--    The default diag_mod=0 is equivalent to diag_mod=2**g_seq_dat_w.
+--    Using diag_mod < 2**g_seq_dat_w can be useful to generate tx seq CNTR
+--    data that is written to a memory that is larger than 2**g_seq_dat_w
+--    addresses. The CNTR values then differ from the memory address values,
+--    which can be useful to ensure that reading e.g. address 2**g_seq_dat_w
+--    yields a different CNTR value than reading 2**(g_seq_dat_w+1).
+
 
 LIBRARY IEEE, common_lib, dp_lib;  -- init value for out_dat when diag_en = '0'
 USE IEEE.std_logic_1164.ALL;