replaced if statement with generate statement

libraries/io/eth/src/vhdl/eth_ip_header_checksum.vhd

@@ -74,6 +74,7 @@ architecture rtl of eth_ip_header_checksum is
 
   constant c_hdr_nof_words      : natural := ceil_div(c_hdr_len, g_data_w);
   constant c_crc_word_span      : natural := 1 + c_hdr_crc_word_hi - c_hdr_crc_word_lo;
+  constant c_crc_in_one_word    : boolean := c_crc_word_span = 1;
 
   signal checksum            : std_logic_vector(c_network_ip_header_checksum_w - 1 downto 0) := (others => '0');
   signal count               : std_logic_vector(31 downto 0);
@@ -92,34 +93,51 @@ begin
   ---------------------------------------------------
   -- process to insert checksum in outgoing stream --
   ---------------------------------------------------
-  p_insert_crc : process(dp_pipeline_src_out, checksum, count, reg_done)
-    variable v_count : natural := 0;
-    variable v_hi    : natural := 0;
-    variable v_lo    : natural := 0;
-  begin
-    v_count := TO_UINT(count);
-    src_out <= dp_pipeline_src_out;
-    nxt_reg_done <= reg_done;
-    if reg_done = '0' and dp_pipeline_src_out.valid = '1' then
-      if v_count = c_hdr_crc_word_hi and v_count = c_hdr_crc_word_lo then -- checksum is in 1 word.
+  gen_insert_crc_one : if c_crc_in_one_word generate -- checksum is in 1 word.
+    p_insert_crc_one : process(dp_pipeline_src_out, checksum, count, reg_done)
+      variable v_count : natural := 0;
+    begin
+      v_count := TO_UINT(count);
+      src_out <= dp_pipeline_src_out;
+      nxt_reg_done <= reg_done;
+      if reg_done = '0' and dp_pipeline_src_out.valid = '1' and v_count = c_hdr_crc_word_hi then
         src_out.data(c_crc_hi_bit_in_word downto c_crc_lo_bit_in_word) <= checksum;
         nxt_reg_done <= '1';
-      elsif v_count = c_hdr_crc_word_hi then 
-        src_out.data(c_crc_hi_bit_in_word downto 0) <= checksum(c_network_ip_header_checksum_w - 1 downto c_network_ip_header_checksum_w - c_crc_hi_bit_in_word - 1);
-      elsif v_count = c_hdr_crc_word_lo then
-        src_out.data(g_data_w - 1 downto c_crc_lo_bit_in_word) <= checksum(g_data_w - c_crc_lo_bit_in_word - 1 downto 0);
-        nxt_reg_done <= '1';
-      elsif v_count < c_hdr_crc_word_hi and v_count > c_hdr_crc_word_lo then
-        v_hi := c_network_ip_header_checksum_w - 1 - c_crc_hi_bit_in_word - 1 - g_data_w * (c_hdr_crc_word_hi - v_count - 1);
-        v_lo := v_hi + 1 - g_data_w;
-        src_out.data(g_data_w - 1 downto 0) <= checksum(v_hi downto v_lo);
       end if;
-    end if;
 
-    if reg_done = '1' and dp_pipeline_src_out.eop = '1' then
-      nxt_reg_done <= '0';
-    end if;
-  end process;
+      if reg_done = '1' and dp_pipeline_src_out.eop = '1' then
+        nxt_reg_done <= '0';
+      end if;
+    end process;
+  end generate;
+
+  gen_insert_crc_multi : if not c_crc_in_one_word generate
+    p_insert_crc_multi : process(dp_pipeline_src_out, checksum, count, reg_done)
+      variable v_count : natural := 0;
+      variable v_hi    : natural := 0;
+      variable v_lo    : natural := 0;
+    begin
+      v_count := TO_UINT(count);
+      src_out <= dp_pipeline_src_out;
+      nxt_reg_done <= reg_done;
+      if reg_done = '0' and dp_pipeline_src_out.valid = '1' then
+        if v_count = c_hdr_crc_word_hi then 
+          src_out.data(c_crc_hi_bit_in_word downto 0) <= checksum(c_network_ip_header_checksum_w - 1 downto c_network_ip_header_checksum_w - c_crc_hi_bit_in_word - 1);
+        elsif v_count = c_hdr_crc_word_lo then
+          src_out.data(g_data_w - 1 downto c_crc_lo_bit_in_word) <= checksum(g_data_w - c_crc_lo_bit_in_word - 1 downto 0);
+          nxt_reg_done <= '1';
+        elsif v_count < c_hdr_crc_word_hi and v_count > c_hdr_crc_word_lo then
+          v_hi := c_network_ip_header_checksum_w - 1 - c_crc_hi_bit_in_word - 1 - g_data_w * (c_hdr_crc_word_hi - v_count - 1);
+          v_lo := v_hi + 1 - g_data_w;
+          src_out.data(g_data_w - 1 downto 0) <= checksum(v_hi downto v_lo);
+        end if;
+      end if;
+  
+      if reg_done = '1' and dp_pipeline_src_out.eop = '1' then
+        nxt_reg_done <= '0';
+      end if;
+    end process;
+  end generate;
 
   ------------------------------------------------------------------------------------------
   -- using common_counter to keep track of the word alignment during checksum calculation --