//======================================================================
//
// sha256_w_mem_regs.v
// -------------------
// The W memory. This version uses 16 32-bit registers as a sliding
// window to generate the 64 words.
//
//
// Author: Joachim Strombergson
// Copyright (c) 2014 NORDUnet A/S
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// - Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// - Neither the name of the NORDUnet nor the names of its contributors may
// be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//======================================================================
module sha256_w_mem(
input wire clk,
input wire reset_n,
input wire [511 : 0] block,
input wire init,
input wire next,
output wire [31 : 0] w
);
//----------------------------------------------------------------
// Registers including update variables and write enable.
//----------------------------------------------------------------
reg [31 : 0] w_mem [0 : 15];
reg [31 : 0] w_mem00_new;
reg [31 : 0] w_mem01_new;
reg [31 : 0] w_mem02_new;
reg [31 : 0] w_mem03_new;
reg [31 : 0] w_mem04_new;
reg [31 : 0] w_mem05_new;
reg [31 : 0] w_mem06_new;
reg [31 : 0] w_mem07_new;
reg [31 : 0] w_mem08_new;
reg [31 : 0] w_mem09_new;
reg [31 : 0] w_mem10_new;
reg [31 : 0] w_mem11_new;
reg [31 : 0] w_mem12_new;
reg [31 : 0] w_mem13_new;
reg [31 : 0] w_mem14_new;
reg [31 : 0] w_mem15_new;
reg w_mem_we;
reg [5 : 0] w_ctr_reg;
reg [5 : 0] w_ctr_new;
reg w_ctr_we;
reg [31 : 0] w_reg;
reg [31 : 0] w_new;
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
reg [31 : 0] w_tmp;
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
assign w = w_tmp;
//----------------------------------------------------------------
// reg_update
// Update functionality for all registers in the core.
// All registers are positive edge triggered with
// asynchronous active low reset.
//----------------------------------------------------------------
always @ (posedge clk or negedge reset_n)
begin : reg_update
integer i;
if (!reset_n)
begin
for (i = 0 ; i < 16 ; i = i + 1)
w_mem[i] <= 32'h0;
w_reg <= 32'h0;
w_ctr_reg <= 6'h0;
end
else
begin
if (w_mem_we)
begin
w_mem[00] <= w_mem00_new;
w_mem[01] <= w_mem01_new;
w_mem[02] <= w_mem02_new;
w_mem[03] <= w_mem03_new;
w_mem[04] <= w_mem04_new;
w_mem[05] <= w_mem05_new;
w_mem[06] <= w_mem06_new;
w_mem[07] <= w_mem07_new;
w_mem[08] <= w_mem08_new;
w_mem[09] <= w_mem09_new;
w_mem[10] <= w_mem10_new;
w_mem[11] <= w_mem11_new;
w_mem[12] <= w_mem12_new;
w_mem[13] <= w_mem13_new;
w_mem[14] <= w_mem14_new;
w_mem[15] <= w_mem15_new;
end
w_reg <= w_new;
if (w_ctr_we)
w_ctr_reg <= w_ctr_new;
end
end // reg_update
//----------------------------------------------------------------
// select_w
//
// Mux for the external read operation. This is where we exract
// the W variable.
//----------------------------------------------------------------
always @*
begin : select_w
if (w_ctr_reg < 16)
w_tmp = w_mem[w_ctr_reg[3 : 0]];
else
w_tmp = w_reg;
end // select_w
//----------------------------------------------------------------
// w_new_logic
//
// Logic that calculates the next value to be inserted into
// the sliding window of the memory.
//----------------------------------------------------------------
always @*
begin : w_mem_update_logic
reg [31 : 0] w_0;
reg [31 : 0] w_1;
reg [31 : 0] w_9;
reg [31 : 0] w_14;
reg [31 : 0] d0;
reg [31 : 0] d1;
w_mem00_new = 32'h00000000;
w_mem01_new = 32'h00000000;
w_mem02_new = 32'h00000000;
w_mem03_new = 32'h00000000;
w_mem04_new = 32'h00000000;
w_mem05_new = 32'h00000000;
w_mem06_new = 32'h00000000;
w_mem07_new = 32'h00000000;
w_mem08_new = 32'h00000000;
w_mem09_new = 32'h00000000;
w_mem10_new = 32'h00000000;
w_mem11_new = 32'h00000000;
w_mem12_new = 32'h00000000;
w_mem13_new = 32'h00000000;
w_mem14_new = 32'h00000000;
w_mem15_new = 32'h00000000;
w_mem_we = 0;
w_0 = w_mem[0];
w_1 = w_mem[1];
w_9 = w_mem[9];
w_14 = w_mem[14];
d0 = {w_1[6 : 0], w_1[31 : 7]} ^
{w_1[17 : 0], w_1[31 : 18]} ^
{3'b000, w_1[31 : 3]};
d1 = {w_14[16 : 0], w_14[31 : 17]} ^
{w_14[18 : 0], w_14[31 : 19]} ^
{10'b0000000000, w_14[31 : 10]};
w_new = d1 + w_9 + d0 + w_0;
if (init)
begin
w_mem00_new = block[511 : 480];
w_mem01_new = block[479 : 448];
w_mem02_new = block[447 : 416];
w_mem03_new = block[415 : 384];
w_mem04_new = block[383 : 352];
w_mem05_new = block[351 : 320];
w_mem06_new = block[319 : 288];
w_mem07_new = block[287 : 256];
w_mem08_new = block[255 : 224];
w_mem09_new = block[223 : 192];
w_mem10_new = block[191 : 160];
w_mem11_new = block[159 : 128];
w_mem12_new = block[127 : 96];
w_mem13_new = block[95 : 64];
w_mem14_new = block[63 : 32];
w_mem15_new = block[31 : 0];
w_mem_we = 1;
end
if (next && (w_ctr_reg > 15))
begin
w_mem00_new = w_mem[01];
w_mem01_new = w_mem[02];
w_mem02_new = w_mem[03];
w_mem03_new = w_mem[04];
w_mem04_new = w_mem[05];
w_mem05_new = w_mem[06];
w_mem06_new = w_mem[07];
w_mem07_new = w_mem[08];
w_mem08_new = w_mem[09];
w_mem09_new = w_mem[10];
w_mem10_new = w_mem[11];
w_mem11_new = w_mem[12];
w_mem12_new = w_mem[13];
w_mem13_new = w_mem[14];
w_mem14_new = w_mem[15];
w_mem15_new = w_new;
w_mem_we = 1;
end
end // w_mem_update_logic
//----------------------------------------------------------------
// w_ctr
// W schedule adress counter. Counts from 0x10 to 0x3f and
// is used to expand the block into words.
//----------------------------------------------------------------
always @*
begin : w_ctr
w_ctr_new = 6'h0;
w_ctr_we = 1'h0;
if (init)
begin
w_ctr_new = 6'h0;
w_ctr_we = 1'h1;
end
if (next)
begin
w_ctr_new = w_ctr_reg + 6'h1;
w_ctr_we = 1'h1;
end
end // w_ctr
endmodule // sha256_w_mem
//======================================================================
// sha256_w_mem.v
//======================================================================
