The SHA-3 algorithm really wants everything to be little-endian, which is

at odds with everything else in our system (including the register
interface to sha3_wrapper). Rather than trying to rewrite sha3, I'll
isolate it in its own little-endian universe by byte-swapping all reads
and writes.

2 files changed, 31 insertions, 23 deletions

diff --git a/src/rtl/sha3.v b/src/rtl/sha3.v
index ee29ba6..a8b41bc 100644
--- a/src/rtl/sha3.v
+++ b/src/rtl/sha3.v
@@ -48,11 +48,25 @@ module sha3(    input wire          clk,
                 input wire          w,

                 input wire [ 8:2]   addr,

                 input wire [32-1:0] din,

-                output reg [32-1:0] dout,

+                output wire [32-1:0] dout,

                 input wire          init,

                 input wire          next,

                 output wire         ready);

 

+

+   /* The SHA-3 algorithm really wants everything to be little-endian,

+    * which is at odds with everything else in our system (including the

+    * register interface to sha3_wrapper). Rather than trying to rewrite

+    * Bernd's beautiful code, we'll just byte-swap all I/O.

+    */

+

+   reg [31:0]                       dout_swap;

+   assign dout = {dout_swap[7:0], dout_swap[15:8], dout_swap[23:16], dout_swap[31:24]};

+

+   wire [31:0]                      din_swap;

+   assign din_swap = {din[7:0], din[15:8], din[23:16], din[31:24]};

+

+

    integer                          i, j;

 

    reg [64-1:0]                     blk[0:24],  // input block

@@ -100,9 +114,9 @@ module sha3(    input wire          clk,
 

    always @*

      //

-     dout = addr[8] ?

-            (~addr[2] ? st [addr[7:3]][31:0] : st [addr[7:3]][63:32]) :

-            (~addr[2] ? blk[addr[7:3]][31:0] : blk[addr[7:3]][63:32]) ;

+     dout_swap = addr[8] ?

+                 (~addr[2] ? st [addr[7:3]][31:0] : st [addr[7:3]][63:32]) :

+                 (~addr[2] ? blk[addr[7:3]][31:0] : blk[addr[7:3]][63:32]) ;

 

 

    always @* begin

@@ -188,12 +202,12 @@ module sha3(    input wire          clk,
 

         end

 

-        if (w && !addr[8])      // only the first half of memory is writeable

+        if (w)

           //

           case (addr[2])

-            1: blk[addr[7:3]][63:32] <= din;

-            0: blk[addr[7:3]][31: 0] <= din;

-          endcase // case (addr[2])

+            1: blk[addr[7:3]][63:32] <= din_swap;

+            0: blk[addr[7:3]][31: 0] <= din_swap;

+          endcase

 

      end

 

diff --git a/src/tb/tb_sha3.v b/src/tb/tb_sha3.v
index 28d06a3..5dd93c4 100644
--- a/src/tb/tb_sha3.v
+++ b/src/tb/tb_sha3.v
@@ -239,8 +239,8 @@ module tb_sha3();
 				 
 			for (i=0; i<50; i=i+1) begin

 				case (i)

-					0:					tb_wr_data = 32'h00000006;		// ...0001 | 10

-					block_words-1:	tb_wr_data = 32'h80000000;		//	1000...

+					0:					tb_wr_data = 32'h06000000;		// ...0001 | 10

+					block_words-1:	tb_wr_data = 32'h00000080;		//	1000...

 					default:			tb_wr_data = 32'h00000000;		

 				endcase

 				tb_addr = {1'b0, i[5:0]};	// increment address

@@ -266,9 +266,7 @@ module tb_sha3();
 				tb_addr = {1'b1, i[5:0]};

 				#(CLK_PERIOD);

 				

-					// swap bytes in the read value

-				for (j=31; j>0; j=j-8)

-					hash_word[j-:8] = tb_rd_data[31-j+:8];

+				hash_word = tb_rd_data;

 				
 				$display("    *** hash_word[%0d]: reference = %08x, calculated = %08x",

 					i, hash_shreg[511-:32], hash_word);

@@ -323,8 +321,8 @@ module tb_sha3();
 				 
 			for (i=0; i<50; i=i+1) begin

 				case (i)

-					0:					tb_wr_data = 32'h06636261;		// ...0001 | 10 | 'cba'

-					block_words-1:	tb_wr_data = 32'h80000000;		//	1000...

+					0:					tb_wr_data = 32'h61626306;		// ...0001 | 10 | 'cba'

+					block_words-1:	tb_wr_data = 32'h00000080;		//	1000...

 					default:			tb_wr_data = 32'h00000000;							

 				endcase

 				tb_addr = {1'b0, i[5:0]};	// increment address

@@ -350,9 +348,7 @@ module tb_sha3();
 				tb_addr = {1'b1, i[5:0]};

 				#(CLK_PERIOD);

 				

-					// swap bytes in the read value

-				for (j=31; j>0; j=j-8)

-					hash_word[j-:8] = tb_rd_data[31-j+:8];

+				hash_word = tb_rd_data;

 				
 				$display("    *** hash_word[%0d]: reference = %08x, calculated = %08x",

 					i, hash_shreg[511-:32], hash_word);

@@ -440,14 +436,14 @@ module tb_sha3();
 						total_bits = total_bits - 32;

 					end else if (total_bits == 0) begin

 							// padding

-						tb_wr_data = 32'h00000006;

+						tb_wr_data = 32'h06000000;

 						tb_addr = {1'b0, i[5:0]};

 						tb_we = 1;
 						#(CLK_PERIOD);

 						total_bits = total_bits - 32;

 					end else if (i == (block_words-1)) begin

 							// more padding

-						tb_wr_data = 32'h80000000;

+						tb_wr_data = 32'h00000080;

 						tb_addr = {1'b0, i[5:0]};

 						tb_we = 1;
 						#(CLK_PERIOD);

@@ -482,9 +478,7 @@ module tb_sha3();
 				tb_addr = {1'b1, i[5:0]};

 				#(CLK_PERIOD);

 				

-					// swap bytes in the read value

-				for (j=31; j>0; j=j-8)

-					hash_word[j-:8] = tb_rd_data[31-j+:8];

+				hash_word = tb_rd_data;

 				
 				$display("    *** hash_word[%0d]: reference = %08x, calculated = %08x",

 					i, hash_shreg[511-:32], hash_word);