Subversion Repositories sha256_hash_core

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-- Author:          Jonny Doin, jdoin@opencores.org, jonnydoin@gmail.com, jonnydoin@gridvortex.com

-- 

-- Create Date:     09:56:30 05/06/2016  

-- Module Name:     sha256_msg_sch - RTL

-- Project Name:    sha256 processor

-- Target Devices:  Spartan-6

-- Tool versions:   ISE 14.7

-- Description: 

--

--      This is the message scheduler datapath for the sha256 processor.

--

------------------------------ COPYRIGHT NOTICE -----------------------------------------------------------------------

--                                                                   

--      This file is part of the SHA256 HASH CORE project http://opencores.org/project,sha256_hash_core

--                                                                   

--      Author(s):      Jonny Doin, jdoin@opencores.org, jonnydoin@gridvortex.com, jonnydoin@gmail.com

--                                                                   

--      Copyright (C) 2016 Jonny Doin

--      -----------------------------

--                                                                   

--      This source file may be used and distributed without restriction provided that this copyright statement is not    

--      removed from the file and that any derivative work contains the original copyright notice and the associated 

--      disclaimer. 

--                                                                   

--      This source file is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser 

--      General Public License as published by the Free Software Foundation; either version 2.1 of the License, or 

--      (at your option) any later version.

--                                                                   

--      This source is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied

--      warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more  

--      details.

--

--      You should have received a copy of the GNU Lesser General Public License along with this source; if not, download 

--      it from http://www.gnu.org/licenses/lgpl.txt

--                                                                   

------------------------------ REVISION HISTORY -----------------------------------------------------------------------

--

-- 2016/05/22   v0.01.0010  [JD]    started development. design of blocks and port interfaces.

-- 2016/06/05   v0.01.0090  [JD]    all modules integrated. testbench for basic test vectors verification.

-- 2016/06/05   v0.01.0095  [JD]    verification failed. misalignment of words in the datapath. 

-- 2016/06/06   v0.01.0100  [JD]    first simulation verification against NIST-FIPS-180-4 test vectors passed.

--

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--  TODO

--  ====

--

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library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

entity sha256_msg_sch is

    port (

        clk_i : in std_logic := 'U';                                            -- system clock

        ce_i : in std_logic := 'U';                                             -- clock input to word shifter

        ld_i : in std_logic := 'U';                                             -- transparent load input to output

        M_i : in std_logic_vector (31 downto 0) := (others => 'U');             -- big endian input message words

        Wt_o : out std_logic_vector (31 downto 0)                               -- message schedule output words

    );

end sha256_msg_sch;

architecture rtl of sha256_msg_sch is

    -- datapath pipeline 

    signal r0 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r1 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r2 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r3 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r4 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r5 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r6 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r7 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r8 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r9 : unsigned (31 downto 0) := (others => '0');              -- internal message register

    signal r10 : unsigned (31 downto 0) := (others => '0');             -- internal message register

    signal r11 : unsigned (31 downto 0) := (others => '0');             -- internal message register

    signal r12 : unsigned (31 downto 0) := (others => '0');             -- internal message register

    signal r13 : unsigned (31 downto 0) := (others => '0');             -- internal message register

    signal r14 : unsigned (31 downto 0) := (others => '0');             -- internal message register

    signal r15 : unsigned (31 downto 0) := (others => '0');             -- internal message register

    -- input mux feedback

    signal next_M : unsigned (31 downto 0);                             -- sum feedback

    -- word shifter wires

    signal next_r0 : unsigned (31 downto 0);

    signal next_r1 : unsigned (31 downto 0);

    signal next_r2 : unsigned (31 downto 0);

    signal next_r3 : unsigned (31 downto 0);

    signal next_r4 : unsigned (31 downto 0);

    signal next_r5 : unsigned (31 downto 0);

    signal next_r6 : unsigned (31 downto 0);

    signal next_r7 : unsigned (31 downto 0);

    signal next_r8 : unsigned (31 downto 0);

    signal next_r9 : unsigned (31 downto 0);

    signal next_r10 : unsigned (31 downto 0);

    signal next_r11 : unsigned (31 downto 0);

    signal next_r12 : unsigned (31 downto 0);

    signal next_r13 : unsigned (31 downto 0);

    signal next_r14 : unsigned (31 downto 0);

    signal next_r15 : unsigned (31 downto 0);

    -- internal modulo adders

    signal sum0 : unsigned (31 downto 0);               -- modulo adder r1 + sum1

    signal sum1 : unsigned (31 downto 0);               -- modulo adder s0 + sum2

    signal sum2 : unsigned (31 downto 0);               -- modulo adder s1 + r10

    -- lower sigma functions

    signal s0 : unsigned (31 downto 0);                 -- lower sigma0 function

    signal s1 : unsigned (31 downto 0);                 -- lower sigma1 function

begin

    --=============================================================================================

    -- MESSAGE SCHEDULER LOGIC

    --=============================================================================================

    -- This logic implements the 256 bytes message schedule as a folded 16 word circular word shifter.

    -- The Add-Rotate-Xor functions s0 and s1 are implemented and fed back to the word shifter.

    -- To avoid a datapath pipeline delay insertion, the output is taken from the r0 input, rather than

    -- the registered r0 output. This lookahead reduces one clock cycle in the overall hash computation,

    -- but increases the combinational path from the input to the processor core.

    -- The next_r0 combinational function has 5 layers of logic, including 3 carry chains.

    -- word shifter register transfer logic

    word_shifter_proc: process (clk_i, ce_i) is

    begin

        if clk_i'event and clk_i = '1' then

            if ce_i = '1' then

                r0 <= next_r0;

                r1 <= next_r1;

                r2 <= next_r2;

                r3 <= next_r3;

                r4 <= next_r4;

                r5 <= next_r5;

                r6 <= next_r6;

                r7 <= next_r7;

                r8 <= next_r8;

                r9 <= next_r9;

                r10 <= next_r10;

                r11 <= next_r11;

                r12 <= next_r12;

                r13 <= next_r13;

                r14 <= next_r14;

                r15 <= next_r15;

            end if;

        end if;

    end process word_shifter_proc;

    -- input mux 

    next_r0_proc: next_r0 <= unsigned(M_i) when ld_i = '1' else next_M;

    next_m_proc:  next_M <= sum0;

    -- word shifter wires

    next_r15_proc: next_r15 <= r0;

    next_r14_proc: next_r14 <= r15;

    next_r13_proc: next_r13 <= r14;

    next_r12_proc: next_r12 <= r13;

    next_r11_proc: next_r11 <= r12;

    next_r10_proc: next_r10 <= r11;

    next_r9_proc: next_r9 <= r10;

    next_r8_proc: next_r8 <= r9;

    next_r7_proc: next_r7 <= r8;

    next_r6_proc: next_r6 <= r7;

    next_r5_proc: next_r5 <= r6;

    next_r4_proc: next_r4 <= r5;

    next_r3_proc: next_r3 <= r4;

    next_r2_proc: next_r2 <= r3;

    next_r1_proc: next_r1 <= r2;

    -- adders 

    sum0_proc: sum0 <= sum1 + r1;

    sum1_proc: sum1 <= sum2 + s0;

    sum2_proc: sum2 <= r10 + s1;

    -- lower sigma functions

    s0_proc: s0 <= (B"000" & r2(31 downto 3)) xor (r2(17 downto 0) & r2(31 downto 18)) xor (r2(6 downto 0) & r2(31 downto 7));

    s1_proc: s1 <= (B"0000000000" & r15(31 downto 10)) xor (r15(18 downto 0) & r15(31 downto 19)) xor (r15(16 downto 0) & r15(31 downto 17));

    --=============================================================================================

    -- OUTPUT LOGIC

    --=============================================================================================

    -- connect output ports

    Wt_o_proc:      Wt_o <= std_logic_vector(next_r0);  -- message scheduler output look ahead

end rtl;