From ac77ca2bfe6d184c13da7ba90e8276ed0fc35765 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joachim=20Stro=CC=88mbergson?= <joachim@secworks.se>
Date: Mon, 21 May 2018 17:50:37 +0200
Subject: Removed the sbox word mux. Removed ports for sbox access in the
 encipher datapath since it now has its own sboxes.

---
 src/rtl/aes_core.v             | 26 +-------------------------
 src/rtl/aes_encipher_block.v   |  3 ---
 src/tb/tb_aes_encipher_block.v | 14 --------------
 3 files changed, 1 insertion(+), 42 deletions(-)

diff --git a/src/rtl/aes_core.v b/src/rtl/aes_core.v
index 5196a1f..7c5720d 100644
--- a/src/rtl/aes_core.v
+++ b/src/rtl/aes_core.v
@@ -94,7 +94,6 @@ module aes_core(
   wire [3 : 0]   enc_round_nr;
   wire [127 : 0] enc_new_block;
   wire           enc_ready;
-  wire [31 : 0]  enc_sboxw;
 
   reg            dec_next;
   wire [3 : 0]   dec_round_nr;
@@ -107,7 +106,6 @@ module aes_core(
 
   wire [31 : 0]  keymem_sboxw;
 
-  reg [31 : 0]   muxed_sboxw;
   wire [31 : 0]  new_sboxw;
 
 
@@ -124,9 +122,6 @@ module aes_core(
                                .round(enc_round_nr),
                                .round_key(round_key),
 
-                               .sboxw(enc_sboxw),
-                               .new_sboxw(new_sboxw),
-
                                .block(block),
                                .new_block(enc_new_block),
                                .ready(enc_ready)
@@ -166,7 +161,7 @@ module aes_core(
                     );
 
 
-  aes_sbox sbox_inst(.sboxw(muxed_sboxw), .new_sboxw(new_sboxw));
+  aes_sbox sbox_inst(.sboxw(keymem_sboxw), .new_sboxw(new_sboxw));
 
 
   //----------------------------------------------------------------
@@ -206,25 +201,6 @@ module aes_core(
     end // reg_update
 
 
-  //----------------------------------------------------------------
-  // sbox_mux
-  //
-  // Controls which of the encipher datapath or the key memory
-  // that gets access to the sbox.
-  //----------------------------------------------------------------
-  always @*
-    begin : sbox_mux
-      if (init_state)
-        begin
-          muxed_sboxw = keymem_sboxw;
-        end
-      else
-        begin
-          muxed_sboxw = enc_sboxw;
-        end
-    end // sbox_mux
-
-
   //----------------------------------------------------------------
   // encdex_mux
   //
diff --git a/src/rtl/aes_encipher_block.v b/src/rtl/aes_encipher_block.v
index c3e672c..c4440d7 100644
--- a/src/rtl/aes_encipher_block.v
+++ b/src/rtl/aes_encipher_block.v
@@ -49,9 +49,6 @@ module aes_encipher_block(
                           output wire [3 : 0]   round,
                           input wire [127 : 0]  round_key,
 
-                          output wire [31 : 0]  sboxw,
-                          input wire  [31 : 0]  new_sboxw,
-
                           input wire [127 : 0]  block,
                           output wire [127 : 0] new_block,
                           output wire           ready
diff --git a/src/tb/tb_aes_encipher_block.v b/src/tb/tb_aes_encipher_block.v
index cc08d8e..87bab2c 100644
--- a/src/tb/tb_aes_encipher_block.v
+++ b/src/tb/tb_aes_encipher_block.v
@@ -74,9 +74,6 @@ module tb_aes_encipher_block();
   wire [3 : 0]   tb_round;
   wire [127 : 0] tb_round_key;
 
-  wire [31 : 0]  tb_sboxw;
-  wire [31 : 0]  tb_new_sboxw;
-
   reg [127 : 0]  tb_block;
   wire [127 : 0] tb_new_block;
 
@@ -92,13 +89,6 @@ module tb_aes_encipher_block();
   //----------------------------------------------------------------
   // Device Under Test.
   //----------------------------------------------------------------
-  // We need an sbox for the tests.
-  aes_sbox sbox(
-                .sboxw(tb_sboxw),
-                .new_sboxw(tb_new_sboxw)
-               );
-
-
   // The device under test.
   aes_encipher_block dut(
                          .clk(tb_clk),
@@ -110,9 +100,6 @@ module tb_aes_encipher_block();
                          .round(tb_round),
                          .round_key(tb_round_key),
 
-                         .sboxw(tb_sboxw),
-                         .new_sboxw(tb_new_sboxw),
-
                          .block(tb_block),
                          .new_block(tb_new_block),
                          .ready(tb_ready)
@@ -172,7 +159,6 @@ module tb_aes_encipher_block();
 
       $display("Internal data values");
       $display("round_key = 0x%016x", dut.round_key);
-      $display("sboxw = 0x%08x, new_sboxw = 0x%08x", dut.sboxw, dut.new_sboxw);
       $display("block_w0_reg = 0x%08x, block_w1_reg = 0x%08x, block_w2_reg = 0x%08x, block_w3_reg = 0x%08x",
                dut.block_w0_reg, dut.block_w1_reg, dut.block_w2_reg, dut.block_w3_reg);
       $display("");
-- 
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