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

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

1 files changed, 31 insertions, 15 deletions

diff --git a/src/rtl/sha3.v b/src/rtl/sha3.v
index ee29ba6..869d142 100644
--- a/src/rtl/sha3.v
+++ b/src/rtl/sha3.v
@@ -44,14 +44,30 @@
 `define SHA3_NUM_ROUNDS         5'd24

 

 module sha3(    input wire          clk,

-                input wire          nreset,

-                input wire          w,

-                input wire [ 8:2]   addr,

-                input wire [32-1:0] din,

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

-                input wire          init,

-                input wire          next,

-                output wire         ready);

+                input wire 	     nreset,

+                input wire 	     w,

+                input wire [ 8:2]    addr,

+                input wire [32-1:0]  din,

+                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, I'll isolate it in its own little-endian

+    * universe by byte-swapping all reads and writes.

+    */

+

+   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;

 

@@ -100,9 +116,9 @@ 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 +204,12 @@ 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