fpga: lib: Update header for AXI4S add/remove bytes

Original-commit: 8af3c0e52df9c3d2585f8579edbf72a7e79fb880

lib/axi4s_sv/axi4s_add_bytes.sv

@@ -7,13 +7,14 @@
 //
 // Description:
 //
-// Add zero filled bytes to a packet.
+//   Add zero filled bytes to a packet. TKEEP is ignored. TUSER should have the
-//   tUser = {error,trailing bytes};
+//   format {error, trailing bytes};
 //
 //  LIMITATIONS
 //    The block only adds bytes to the beginning of a word.
 //
 // Parameters:
+//
 //   ADD_START  - Add bytes before this point (0 means start)
 //                0 is the only supported value right now
 //   ADD_BYTES  - Number of bytes to add
@@ -23,6 +24,7 @@
 //                it means the extra space may be added before
 //                we setup the values we want to overwrite onto
 //                that space.
+//
 
 module axi4s_add_bytes #(
   int ADD_START = 0,

lib/axi4s_sv/axi4s_remove_bytes.sv

@@ -6,18 +6,19 @@
 // Module : axi4s_remove_bytes
 //
 // Description:
-//   Remove bytes from a packet.  1 removal can happen per
+//
-//   packet.  The removal is made by delaying the output
+//   Remove bytes from a packet.  1 removal can happen per packet.  The removal
-//   by a clock, and then combining the new and old word
+//   is made by delaying the output by a clock, and then combining the new and
-//   and providing a combination of shifted words.
+//   old word and providing a combination of shifted words. This implementation
-//   This implementation requires that the user field
+//   requires that the user field holds the number of valid bytes in the word,
-//   holds the number of valid bytes in the word, and the MSB of the user field
+//   and the MSB of the user field indicates if the MAC had an error.
-//   indicates if the MAC had an error.
 //
 //   The block will hold off the input if it goes to the BONUS State.
 //
-//   This block is intended to remove data from the beginning or middle
+//   This block is intended to remove data from the beginning or middle of a
-//   of a packet.  You can truncate a packet by setting REM_END to -1.
+//   packet.  You can truncate a packet by setting REM_END to -1.
+//
+//   TKEEP is not used. TUSER should have the format {error, trailing bytes};
 //
 //  LIMITATIONS
 //    The block will set the error bit if you put in a packet between
@@ -27,6 +28,7 @@
 //    Packets must be terminated with tlast.
 //
 // Parameters:
+//
 //   REM_START  - First byte to remove (0 means start)
 //   REM_END    - Last byte to remove (-1 means truncate from REM START)
 //