Connected the new S-boxes and collapsed the SubBytes operation into one cycle. This provides a speedup for Encipher with 2.1x.

1 files changed, 12 insertions, 37 deletions

diff --git a/src/rtl/aes_encipher_block.v b/src/rtl/aes_encipher_block.v
index 29a555e..c1961bd 100644
--- a/src/rtl/aes_encipher_block.v
+++ b/src/rtl/aes_encipher_block.v
@@ -290,6 +290,11 @@ module aes_encipher_block(
       block_w2_we = 1'b0;
       block_w3_we = 1'b0;
 
+      sboxw0 = block_w0_reg;
+      sboxw1 = block_w1_reg;
+      sboxw2 = block_w2_reg;
+      sboxw3 = block_w3_reg;
+
       old_block          = {block_w0_reg, block_w1_reg, block_w2_reg, block_w3_reg};
       shiftrows_block    = shiftrows(old_block);
       mixcolumns_block   = mixcolumns(shiftrows_block);
@@ -309,33 +314,11 @@ module aes_encipher_block(
 
         SBOX_UPDATE:
           begin
-            block_new = {new_sboxw, new_sboxw, new_sboxw, new_sboxw};
-
-            case (sword_ctr_reg)
-              2'h0:
-                begin
-                  muxed_sboxw = block_w0_reg;
-                  block_w0_we = 1'b1;
-                end
-
-              2'h1:
-                begin
-                  muxed_sboxw = block_w1_reg;
-                  block_w1_we = 1'b1;
-                end
-
-              2'h2:
-                begin
-                  muxed_sboxw = block_w2_reg;
-                  block_w2_we = 1'b1;
-                end
-
-              2'h3:
-                begin
-                  muxed_sboxw = block_w3_reg;
-                  block_w3_we = 1'b1;
-                end
-            endcase // case (sbox_mux_ctrl_reg)
+            block_new = {new_sboxw0, new_sboxw1, new_sboxw2, new_sboxw3};
+            block_w0_we = 1'b1;
+            block_w1_we = 1'b1;
+            block_w2_we = 1'b1;
+            block_w3_we = 1'b1;
           end
 
         MAIN_UPDATE:
@@ -427,8 +410,6 @@ module aes_encipher_block(
           num_rounds = AES128_ROUNDS;
         end
 
-      sword_ctr_inc = 1'b0;
-      sword_ctr_rst = 1'b0;
       round_ctr_inc = 1'b0;
       round_ctr_rst = 1'b0;
       ready_new     = 1'b0;
@@ -453,7 +434,6 @@ module aes_encipher_block(
         CTRL_INIT:
           begin
             round_ctr_inc = 1'b1;
-            sword_ctr_rst = 1'b1;
             update_type   = INIT_UPDATE;
             enc_ctrl_new  = CTRL_SBOX;
             enc_ctrl_we   = 1'b1;
@@ -461,18 +441,13 @@ module aes_encipher_block(
 
         CTRL_SBOX:
           begin
-            sword_ctr_inc = 1'b1;
             update_type   = SBOX_UPDATE;
-            if (sword_ctr_reg == 2'h3)
-              begin
-                enc_ctrl_new  = CTRL_MAIN;
-                enc_ctrl_we   = 1'b1;
-              end
+            enc_ctrl_new  = CTRL_MAIN;
+            enc_ctrl_we   = 1'b1;
           end
 
         CTRL_MAIN:
           begin
-            sword_ctr_rst = 1'b1;
             round_ctr_inc = 1'b1;
             if (round_ctr_reg < num_rounds)
               begin