Only det the valid data bits for 16-bit transfers. This such that the...

Only det the valid data bits for 16-bit transfers.  This such that the data-stable-check only checks used bits.

src/vme_data_bus.vhd

@@ -571,8 +571,12 @@ begin
           -- Conclusion:
           -- The D lines always carry the least significant bits.
           -- If we run MBLT then the A lines with carry the MSB.
-          -- 
-          cur_data(31 downto 0) := vme_data_i;
+          cur_data(15 downto 0) := vme_data_i;
+          if (l_addr[0] = '0' or l_transfer_mode = MBLT) then
+            cur_data(31 downto 16) := vme_data_i;
+          else
+            cur_data(31 downto 16) := (others => '0');
+          end if;
           case l_transfer_mode is
             when SINGLE | BLT =>
               -- l_data_r(31 downto 0) => vme_data_i;