//------------------------------------------------------------------------------
//
// ecdsa256_modular_reductor.v
// -----------------------------------------------------------------------------
// Modular reductor.
//
// Authors: Pavel Shatov
//
// Copyright (c) 2015-2016, NORDUnet A/S
//
// 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 ecdsa256_modular_reductor
(
clk, rst_n,
ena, rdy,
x_addr, p_addr, p_wren,
x_din, p_dout
);
//
// Constants
//
localparam OPERAND_NUM_WORDS = 8;
localparam WORD_COUNTER_WIDTH = 3;
//
// Handy Numbers
//
localparam [WORD_COUNTER_WIDTH:0] WORD_INDEX_ZERO = 0;
localparam [WORD_COUNTER_WIDTH:0] WORD_INDEX_LAST = 2 * OPERAND_NUM_WORDS - 1;
//
// Handy Functions
//
function [WORD_COUNTER_WIDTH:0] WORD_INDEX_PREVIOUS_OR_LAST;
input [WORD_COUNTER_WIDTH:0] WORD_INDEX_CURRENT;
begin
WORD_INDEX_PREVIOUS_OR_LAST = (WORD_INDEX_CURRENT > WORD_INDEX_ZERO) ?
WORD_INDEX_CURRENT - 1'b1 : WORD_INDEX_LAST;
end
endfunction
//
// Ports
//
input wire clk; // system clock
input wire rst_n; // active-low async reset
input wire ena; // enable input
output wire rdy; // ready output
output wire [WORD_COUNTER_WIDTH-0:0] x_addr; // index of current X word
output wire [WORD_COUNTER_WIDTH-1:0] p_addr; // index of current P word
output wire p_wren; // store current P word now
input wire [ 31:0] x_din; // X
output wire [ 31:0] p_dout; // P = X mod N
//
// Word Indices
//
reg [WORD_COUNTER_WIDTH:0] index_x;
/* map registers to output ports */
assign x_addr = index_x;
//
// FSM
//
localparam FSM_SHREG_WIDTH = (2 * OPERAND_NUM_WORDS + 1) + (5 * 2) + 1;
reg [FSM_SHREG_WIDTH-1:0] fsm_shreg;
assign rdy = fsm_shreg[0];
wire [2 * OPERAND_NUM_WORDS - 1:0] fsm_shreg_inc_index_x = fsm_shreg[FSM_SHREG_WIDTH - 0*OPERAND_NUM_WORDS - 1 -: 2 * OPERAND_NUM_WORDS];
wire [2 * OPERAND_NUM_WORDS - 1:0] fsm_shreg_store_word_z = fsm_shreg[FSM_SHREG_WIDTH - 0*OPERAND_NUM_WORDS - 2 -: 2 * OPERAND_NUM_WORDS];
wire [2 * 5 - 1:0] fsm_shreg_reduce_stages = fsm_shreg[ 1 +: 2 * 5];
wire [5-1:0] fsm_shreg_reduce_stage_start;
wire [5-1:0] fsm_shreg_reduce_stage_stop;
genvar s;
generate for (s=0; s<5; s=s+1)
begin : gen_fsm_shreg_reduce_stages
assign fsm_shreg_reduce_stage_start[5 - (s + 1)] = fsm_shreg_reduce_stages[2 * (5 - s) - 1];
assign fsm_shreg_reduce_stage_stop[5 - (s + 1)] = fsm_shreg_reduce_stages[2 * (5 - s) - 2];
end
endgenerate
wire inc_index_x = |fsm_shreg_inc_index_x;
wire store_word_z = |fsm_shreg_store_word_z;
wire reduce_start = |fsm_shreg_reduce_stage_start;
wire reduce_stop = |fsm_shreg_reduce_stage_stop;
wire store_p = fsm_shreg_reduce_stage_stop[0];
wire reduce_adder0_done;
wire reduce_adder1_done;
wire reduce_subtractor_done;
wire reduce_done_all = reduce_adder0_done & reduce_adder1_done & reduce_subtractor_done;
always @(posedge clk or negedge rst_n)
//
if (rst_n == 1'b0)
//
fsm_shreg <= {{FSM_SHREG_WIDTH-1{1'b0}}, 1'b1};
//
else begin
//
if (rdy)
//
fsm_shreg <= {ena, {FSM_SHREG_WIDTH-2{1'b0}}, ~ena};
//
else if (!reduce_stop || reduce_done_all)
//
fsm_shreg <= {1'b0, fsm_shreg[FSM_SHREG_WIDTH-1:1]};
//
end
//
// Word Index Increment Logic
//
always @(posedge clk)
//
if (rdy)
//
index_x <= WORD_INDEX_LAST;
//
else if (inc_index_x)
//
index_x <= WORD_INDEX_PREVIOUS_OR_LAST(index_x);
//
// Look-up Table
//
//
// Take a look at the corresponding C model for more information
// on how exactly the math behind reduction works. The first step
// is to assemble nine 256-bit values ("z-words") from 32-bit parts
// of the full 512-bit product ("c-word"). The problem with z5 is
// that it contains c13 two times. This implementation scans from
// c15 to c0 and writes current part of c-word into corresponding
// parts of z-words. Since those 32-bit parts are stored in block
// memories, one source word can only be written to one location in
// every z-word at a time. The trick is to delay c13 and then write
// the delayed value at the corresponding location in z5 instead of
// the next c12. "z_save" flag is used to indicate that the current
// word should be delayed and written once again during the next cycle.
//
reg [9*WORD_COUNTER_WIDTH-1:0] z_addr; //
reg [9 -1:0] z_wren; //
reg [9 -1:0] z_mask; // mask input to store zero word
reg [9 -1:0] z_save; // save previous word once again
always @(posedge clk)
//
if (inc_index_x)
//
case (index_x)
//
// s9 s8 s7 s6 s5 s4 s3 s2 s1
// || || || || || || || || ||
4'd00: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd00};
4'd01: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd01};
4'd02: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd02};
4'd03: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd03};
4'd04: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd04};
4'd05: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd05};
4'd06: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd06};
4'd07: z_addr <= {3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'dx, 3'd07};
4'd08: z_addr <= {3'd02, 3'd03, 3'd04, 3'd06, 3'd07, 3'd00, 3'd00, 3'd00, 3'dx};
4'd09: z_addr <= {3'd03, 3'd04, 3'd06, 3'd03, 3'd00, 3'd01, 3'd01, 3'd01, 3'dx};
4'd10: z_addr <= {3'd04, 3'd05, 3'd05, 3'd07, 3'd01, 3'd02, 3'd02, 3'd02, 3'dx};
4'd11: z_addr <= {3'd05, 3'd06, 3'd07, 3'd00, 3'd02, 3'd03, 3'd07, 3'd03, 3'dx};
4'd12: z_addr <= {3'd06, 3'd07, 3'd00, 3'd01, 3'd06, 3'd04, 3'd03, 3'd04, 3'dx};
4'd13: z_addr <= {3'd07, 3'd00, 3'd01, 3'd02, 3'd03, 3'd05, 3'd04, 3'd05, 3'dx};
4'd14: z_addr <= {3'd00, 3'd01, 3'd02, 3'd04, 3'd04, 3'd06, 3'd05, 3'd06, 3'dx};
4'd15: z_addr <= {3'd01, 3'd02, 3'd03, 3'd05, 3'd05, 3'd07, 3'd06, 3'd07, 3'dx};
//
default: z_addr <= {9*WORD_COUNTER_WIDTH{1'bX}};
//
endcase
always @(posedge clk)
//
case (index_x)
//
// 9 8 7 6 5 4 3 2 1
// | | | | | | | | |
4'd00: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd01: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd02: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd03: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd04: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd05: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd06: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd07: z_wren <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1};
4'd08: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd09: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd10: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd11: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd12: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd13: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd14: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
4'd15: z_wren <= {1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b1, 1'b0};
//
default: z_wren <= {9{1'b0}};
//
endcase
always @(posedge clk)
//
if (inc_index_x)
//
case (index_x)
//
// 9 8 7 6 5 4 3 2 1
// | | | | | | | | |
4'd00: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd01: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd02: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd03: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd04: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd05: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd06: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd07: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd08: z_mask <= {1'b1, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0, 1'b1, 1'b1, 1'b0};
4'd09: z_mask <= {1'b0, 1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b1, 1'b1, 1'b0};
4'd10: z_mask <= {1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0, 1'b1, 1'b1, 1'b0};
4'd11: z_mask <= {1'b0, 1'b1, 1'b0, 1'b0, 1'b0, 1'b1, 1'b1, 1'b0, 1'b0};
4'd12: z_mask <= {1'b1, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0};
4'd13: z_mask <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0};
4'd14: z_mask <= {1'b0, 1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd15: z_mask <= {1'b0, 1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
//
default: z_mask <= {9{1'bX}};
//
endcase
always @(posedge clk)
//
if (inc_index_x)
//
case (index_x)
//
// 9 8 7 6 5 4 3 2 1
// | | | | | | | | |
4'd00: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd01: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd02: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd03: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd04: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd05: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd06: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd07: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd08: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd09: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd10: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd11: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd12: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b1, 1'b0, 1'b0, 1'b0, 1'b0};
4'd13: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd14: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
4'd15: z_save <= {1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0};
//
default: z_save <= {9{1'bX}};
//
endcase
//
// Modulus
//
wire [WORD_COUNTER_WIDTH-1:0] n_addr;
wire [ 32-1:0] n_dout;
ecdsa256_modulus_distmem p256_q_rom
(
.clk (clk),
.b_addr (n_addr),
.b_out (n_dout)
);
//
// Intermediate Numbers
//
reg [WORD_COUNTER_WIDTH-1:0] reduce_z_addr[1:9];
wire [ 32-1:0] reduce_z_dout[1:9];
reg [31: 0] x_din_dly;
always @(posedge clk)
//
x_din_dly <= x_din;
genvar z;
generate for (z=1; z<=9; z=z+1)
//
begin : gen_z_bram
//
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_c_inst
(
.clk (clk),
.a_addr (z_addr[(z-1) * WORD_COUNTER_WIDTH +: WORD_COUNTER_WIDTH]),
.a_wr (z_wren[z-1] & store_word_z),
.a_in (z_mask[z-1] ? {32{1'b0}} : (z_save[z-1] ? x_din_dly : x_din)),
.a_out (),
.b_addr (reduce_z_addr[z]),
.b_out (reduce_z_dout[z])
);
//
end
//
endgenerate
wire [ 32-1:0] bram_sum0_wr_din;
wire [WORD_COUNTER_WIDTH-1:0] bram_sum0_wr_addr;
wire bram_sum0_wr_wren;
wire [ 32-1:0] bram_sum1_wr_din;
wire [WORD_COUNTER_WIDTH-1:0] bram_sum1_wr_addr;
wire bram_sum1_wr_wren;
wire [ 32-1:0] bram_diff_wr_din;
wire [WORD_COUNTER_WIDTH-1:0] bram_diff_wr_addr;
wire bram_diff_wr_wren;
wire [ 32-1:0] bram_sum0_rd_dout;
reg [WORD_COUNTER_WIDTH-1:0] bram_sum0_rd_addr;
wire [ 32-1:0] bram_sum1_rd_dout;
reg [WORD_COUNTER_WIDTH-1:0] bram_sum1_rd_addr;
wire [ 32-1:0] bram_diff_rd_dout;
reg [WORD_COUNTER_WIDTH-1:0] bram_diff_rd_addr;
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_sum0_inst
(
.clk (clk),
.a_addr (bram_sum0_wr_addr),
.a_wr (bram_sum0_wr_wren),
.a_in (bram_sum0_wr_din),
.a_out (),
.b_addr (bram_sum0_rd_addr),
.b_out (bram_sum0_rd_dout)
);
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_sum1_inst
(
.clk (clk),
.a_addr (bram_sum1_wr_addr),
.a_wr (bram_sum1_wr_wren),
.a_in (bram_sum1_wr_din),
.a_out (),
.b_addr (bram_sum1_rd_addr),
.b_out (bram_sum1_rd_dout)
);
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_diff_inst
(
.clk (clk),
.a_addr (bram_diff_wr_addr),
.a_wr (bram_diff_wr_wren),
.a_in (bram_diff_wr_din),
.a_out (),
.b_addr (bram_diff_rd_addr),
.b_out (bram_diff_rd_dout)
);
wire [WORD_COUNTER_WIDTH-1:0] adder0_ab_addr;
wire [WORD_COUNTER_WIDTH-1:0] adder1_ab_addr;
wire [WORD_COUNTER_WIDTH-1:0] subtractor_ab_addr;
reg [ 32-1:0] adder0_a_din;
reg [ 32-1:0] adder0_b_din;
reg [ 32-1:0] adder1_a_din;
reg [ 32-1:0] adder1_b_din;
reg [ 32-1:0] subtractor_a_din;
reg [ 32-1:0] subtractor_b_din;
// n_addr - only 1 output, because all modules are in sync
modular_adder #
(
.OPERAND_NUM_WORDS (OPERAND_NUM_WORDS),
.WORD_COUNTER_WIDTH (WORD_COUNTER_WIDTH)
)
adder_inst0
(
.clk (clk),
.rst_n (rst_n),
.ena (reduce_start),
.rdy (reduce_adder0_done),
.ab_addr (adder0_ab_addr),
.n_addr (),
.s_addr (bram_sum0_wr_addr),
.s_wren (bram_sum0_wr_wren),
.a_din (adder0_a_din),
.b_din (adder0_b_din),
.n_din (n_dout),
.s_dout (bram_sum0_wr_din)
);
modular_adder #
(
.OPERAND_NUM_WORDS (OPERAND_NUM_WORDS),
.WORD_COUNTER_WIDTH (WORD_COUNTER_WIDTH)
)
adder_inst1
(
.clk (clk),
.rst_n (rst_n),
.ena (reduce_start),
.rdy (reduce_adder1_done),
.ab_addr (adder1_ab_addr),
.n_addr (),
.s_addr (bram_sum1_wr_addr),
.s_wren (bram_sum1_wr_wren),
.a_din (adder1_a_din),
.b_din (adder1_b_din),
.n_din (n_dout),
.s_dout (bram_sum1_wr_din)
);
modular_subtractor #
(
.OPERAND_NUM_WORDS (OPERAND_NUM_WORDS),
.WORD_COUNTER_WIDTH (WORD_COUNTER_WIDTH)
)
subtractor_inst
(
.clk (clk),
.rst_n (rst_n),
.ena (reduce_start),
.rdy (reduce_subtractor_done),
.ab_addr (subtractor_ab_addr),
.n_addr (n_addr),
.d_addr (bram_diff_wr_addr),
.d_wren (bram_diff_wr_wren),
.a_din (subtractor_a_din),
.b_din (subtractor_b_din),
.n_din (n_dout),
.d_dout (bram_diff_wr_din)
);
//
// Address (Operand) Selector
//
always @(*)
//
case (fsm_shreg_reduce_stage_stop)
//
5'b10000: begin
reduce_z_addr[1] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[2] = adder0_ab_addr;
reduce_z_addr[3] = adder1_ab_addr;
reduce_z_addr[4] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[5] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[6] = subtractor_ab_addr;
reduce_z_addr[7] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[8] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[9] = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum0_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum1_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
bram_diff_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
end
//
5'b01000: begin
reduce_z_addr[1] = adder0_ab_addr;
reduce_z_addr[2] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[3] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[4] = adder1_ab_addr;
reduce_z_addr[5] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[6] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[7] = subtractor_ab_addr;
reduce_z_addr[8] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[9] = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum0_rd_addr = adder0_ab_addr;
bram_sum1_rd_addr = adder1_ab_addr;
bram_diff_rd_addr = subtractor_ab_addr;
end
//
5'b00100: begin
reduce_z_addr[1] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[2] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[3] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[4] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[5] = adder0_ab_addr;
reduce_z_addr[6] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[7] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[8] = subtractor_ab_addr;
reduce_z_addr[9] = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum0_rd_addr = adder0_ab_addr;
bram_sum1_rd_addr = adder1_ab_addr;
bram_diff_rd_addr = subtractor_ab_addr;
end
//
5'b00010: begin
reduce_z_addr[1] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[2] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[3] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[4] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[5] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[6] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[7] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[8] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[9] = subtractor_ab_addr;
bram_sum0_rd_addr = adder0_ab_addr;
bram_sum1_rd_addr = adder0_ab_addr;
bram_diff_rd_addr = subtractor_ab_addr;
end
//
5'b00001: begin
reduce_z_addr[1] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[2] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[3] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[4] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[5] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[6] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[7] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[8] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[9] = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum0_rd_addr = adder0_ab_addr;
bram_sum1_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
bram_diff_rd_addr = adder0_ab_addr;
end
//
default: begin
reduce_z_addr[1] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[2] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[3] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[4] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[5] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[6] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[7] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[8] = {WORD_COUNTER_WIDTH{1'bX}};
reduce_z_addr[9] = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum0_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
bram_sum1_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
bram_diff_rd_addr = {WORD_COUNTER_WIDTH{1'bX}};
end
//
endcase
//
// adder 0
//
always @(*) begin
//
case (fsm_shreg_reduce_stage_stop)
5'b10000: adder0_a_din = reduce_z_dout[2];
5'b01000: adder0_a_din = bram_sum0_rd_dout;
5'b00100: adder0_a_din = bram_sum0_rd_dout;
5'b00010: adder0_a_din = bram_sum0_rd_dout;
5'b00001: adder0_a_din = bram_sum0_rd_dout;
default: adder0_a_din = {32{1'bX}};
endcase
//
case (fsm_shreg_reduce_stage_stop)
5'b10000: adder0_b_din = reduce_z_dout[2];
5'b01000: adder0_b_din = reduce_z_dout[1];
5'b00100: adder0_b_din = reduce_z_dout[5];
5'b00010: adder0_b_din = bram_sum1_rd_dout;
5'b00001: adder0_b_din = bram_diff_rd_dout;
default: adder0_b_din = {32{1'bX}};
endcase
//
end
//
// adder 1
//
always @(*) begin
//
case (fsm_shreg_reduce_stage_stop)
5'b10000: adder1_a_din = reduce_z_dout[3];
5'b01000: adder1_a_din = bram_sum1_rd_dout;
5'b00100: adder1_a_din = bram_sum1_rd_dout;
5'b00010: adder1_a_din = {32{1'bX}};
5'b00001: adder1_a_din = {32{1'bX}};
default: adder1_a_din = {32{1'bX}};
endcase
//
case (fsm_shreg_reduce_stage_stop)
5'b10000: adder1_b_din = reduce_z_dout[3];
5'b01000: adder1_b_din = reduce_z_dout[4];
5'b00100: adder1_b_din = {32{1'b0}};
5'b00010: adder1_b_din = {32{1'bX}};
5'b00001: adder1_b_din = {32{1'bX}};
default: adder1_b_din = {32{1'bX}};
endcase
//
end
//
// subtractor
//
always @(*) begin
//
case (fsm_shreg_reduce_stage_stop)
5'b10000: subtractor_a_din = {32{1'b0}};
5'b01000: subtractor_a_din = bram_diff_rd_dout;
5'b00100: subtractor_a_din = bram_diff_rd_dout;
5'b00010: subtractor_a_din = bram_diff_rd_dout;
5'b00001: subtractor_a_din = {32{1'bX}};
default: subtractor_a_din = {32{1'bX}};
endcase
//
case (fsm_shreg_reduce_stage_stop)
5'b10000: subtractor_b_din = reduce_z_dout[6];
5'b01000: subtractor_b_din = reduce_z_dout[7];
5'b00100: subtractor_b_din = reduce_z_dout[8];
5'b00010: subtractor_b_din = reduce_z_dout[9];
5'b00001: subtractor_b_din = {32{1'bX}};
default: subtractor_b_din = {32{1'bX}};
endcase
//
end
//
// Address Mapping
//
assign p_addr = bram_sum0_wr_addr;
assign p_wren = bram_sum0_wr_wren & store_p;
assign p_dout = bram_sum0_wr_din;
endmodule
//------------------------------------------------------------------------------
// End-of-File
//------------------------------------------------------------------------------
