//------------------------------------------------------------------------------
//
// ecdsa384_base_point_multiplier.v
// -----------------------------------------------------------------------------
// ECDSA base point scalar multiplier.
//
// Authors: Pavel Shatov
//
// Copyright (c) 2016, 2018 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 ecdsa384_base_point_multiplier
(
clk, rst_n,
ena, rdy,
k_addr, rxy_addr,
rx_wren, ry_wren,
k_din,
rxy_dout
);
//
// Microcode Header
//
`include "ecdsa_uop.vh"
//
// Ports
//
input clk; // system clock
input rst_n; // active-low async reset
input ena; // enable input
output rdy; // ready output
output [ 3:0] k_addr; //
output [ 3:0] rxy_addr; //
output rx_wren; //
output ry_wren; //
input [31:0] k_din; //
output [31:0] rxy_dout; //
//
// FSM
//
localparam [4:0] FSM_STATE_IDLE = 5'd00;
localparam [4:0] FSM_STATE_PREPARE_TRIG = 5'd01;
localparam [4:0] FSM_STATE_PREPARE_WAIT = 5'd02;
localparam [4:0] FSM_STATE_CYCLE_DBL_TRIG = 5'd03;
localparam [4:0] FSM_STATE_CYCLE_DBL_WAIT = 5'd04;
localparam [4:0] FSM_STATE_CYCLE_ADD_TRIG = 5'd05;
localparam [4:0] FSM_STATE_CYCLE_ADD_WAIT = 5'd06;
localparam [4:0] FSM_STATE_CYCLE_ADD_EXTRA_TRIG = 5'd07;
localparam [4:0] FSM_STATE_CYCLE_ADD_EXTRA_WAIT = 5'd08;
localparam [4:0] FSM_STATE_AFTER_CYCLE_TRIG = 5'd09;
localparam [4:0] FSM_STATE_AFTER_CYCLE_WAIT = 5'd10;
localparam [4:0] FSM_STATE_INVERT_TRIG = 5'd11;
localparam [4:0] FSM_STATE_INVERT_WAIT = 5'd12;
localparam [4:0] FSM_STATE_CONVERT_TRIG = 5'd13;
localparam [4:0] FSM_STATE_CONVERT_WAIT = 5'd14;
localparam [4:0] FSM_STATE_CONVERT_EXTRA_TRIG = 5'd15;
localparam [4:0] FSM_STATE_CONVERT_EXTRA_WAIT = 5'd16;
localparam [4:0] FSM_STATE_DONE = 5'd17;
reg [4:0] fsm_state = FSM_STATE_IDLE;
reg [4:0] fsm_state_next;
//
// Round Counter
//
reg [8:0] bit_counter;
wire [8:0] bit_counter_last = 9'h17F; // 384
wire [8:0] bit_counter_zero = 9'h000; // 0
wire [8:0] bit_counter_prev =
(bit_counter > bit_counter_zero) ? bit_counter - 1'b1 : bit_counter_last;
assign k_addr = bit_counter[8:5];
//
// Worker Trigger Logic
//
reg worker_trig = 1'b0;
wire worker_done;
wire fsm_wait_done = !worker_trig && worker_done;
always @(posedge clk or negedge rst_n)
//
if (rst_n == 1'b0) worker_trig <= 1'b0;
else case (fsm_state)
FSM_STATE_PREPARE_TRIG,
FSM_STATE_CYCLE_DBL_TRIG,
FSM_STATE_CYCLE_ADD_TRIG,
FSM_STATE_CYCLE_ADD_EXTRA_TRIG,
FSM_STATE_AFTER_CYCLE_TRIG,
FSM_STATE_INVERT_TRIG,
FSM_STATE_CONVERT_TRIG,
FSM_STATE_CONVERT_EXTRA_TRIG: worker_trig <= 1'b1;
default: worker_trig <= 1'b0;
endcase
//
// Round Counter Increment Logic
//
always @(posedge clk)
//
case (fsm_state_next)
FSM_STATE_PREPARE_TRIG: bit_counter <= bit_counter_last;
FSM_STATE_AFTER_CYCLE_TRIG: bit_counter <= bit_counter_prev;
endcase
//
// Final Cycle Detection Logic
//
wire [ 3: 0] fsm_state_after_cycle = (bit_counter == bit_counter_last) ?
FSM_STATE_INVERT_TRIG : FSM_STATE_CYCLE_DBL_TRIG;
//
// K Latch
//
reg [31:0] k_din_shreg;
wire [4:0] k_bit_index = bit_counter[4:0];
always @(posedge clk)
//
if (fsm_state_next == FSM_STATE_CYCLE_DBL_TRIG)
//
if (k_bit_index == 5'd31) k_din_shreg <= k_din;
else k_din_shreg <= {k_din_shreg[30:0], ~k_din_shreg[31]};
//
// Worker Flags
//
wire worker_flagz_sz;
wire worker_flagz_rz;
wire worker_flagz_e;
wire worker_flagz_f;
wire [2:0] worker_flagz_cycle_add =
{worker_flagz_sz, worker_flagz_e, worker_flagz_f};
wire worker_flagz_convert_extra =
worker_flagz_rz;
//
// Worker Offset Logic
//
reg [UOP_ADDR_WIDTH-1:0] worker_offset;
always @(posedge clk)
//
case (fsm_state)
FSM_STATE_PREPARE_TRIG: worker_offset <= UOP_OFFSET_PREPARE;
FSM_STATE_CYCLE_DBL_TRIG: worker_offset <= UOP_OFFSET_CYCLE_DOUBLE;
FSM_STATE_CYCLE_ADD_TRIG: worker_offset <= UOP_OFFSET_CYCLE_ADD;
FSM_STATE_CYCLE_ADD_EXTRA_TRIG:
// {sz, e, f}
casez(worker_flagz_cycle_add)
3'b1??: worker_offset <= UOP_OFFSET_CYCLE_ADD_AT_INFINITY;
3'b011: worker_offset <= UOP_OFFSET_CYCLE_ADD_SAME_X_SAME_Y;
3'b010: worker_offset <= UOP_OFFSET_CYCLE_ADD_SAME_X;
3'b00?: worker_offset <= UOP_OFFSET_CYCLE_ADD_REGULAR;
endcase
FSM_STATE_AFTER_CYCLE_TRIG: worker_offset <= k_din_shreg[31] ?
UOP_OFFSET_CYCLE_K1 : UOP_OFFSET_CYCLE_K0;
FSM_STATE_INVERT_TRIG: worker_offset <= UOP_OFFSET_INVERT;
FSM_STATE_CONVERT_TRIG: worker_offset <= UOP_OFFSET_CONVERT;
FSM_STATE_CONVERT_EXTRA_TRIG: worker_offset <= worker_flagz_convert_extra ?
UOP_OFFSET_CONVERT_AT_INFINITY : UOP_OFFSET_CONVERT_REGULAR;
default: worker_offset <= {UOP_ADDR_WIDTH{1'bX}};
endcase
//
// FSM Process
//
always @(posedge clk or negedge rst_n)
//
if (rst_n == 1'b0) fsm_state <= FSM_STATE_IDLE;
else fsm_state <= fsm_state_next;
//
// FSM Transition Logic
//
always @* begin
//
fsm_state_next = FSM_STATE_IDLE;
//
case (fsm_state)
FSM_STATE_IDLE: fsm_state_next = ena ? FSM_STATE_PREPARE_TRIG : FSM_STATE_IDLE;
FSM_STATE_PREPARE_TRIG: fsm_state_next = FSM_STATE_PREPARE_WAIT ;
FSM_STATE_PREPARE_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_CYCLE_DBL_TRIG : FSM_STATE_PREPARE_WAIT;
FSM_STATE_CYCLE_DBL_TRIG: fsm_state_next = FSM_STATE_CYCLE_DBL_WAIT ;
FSM_STATE_CYCLE_DBL_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_CYCLE_ADD_TRIG : FSM_STATE_CYCLE_DBL_WAIT;
FSM_STATE_CYCLE_ADD_TRIG: fsm_state_next = FSM_STATE_CYCLE_ADD_WAIT ;
FSM_STATE_CYCLE_ADD_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_CYCLE_ADD_EXTRA_TRIG : FSM_STATE_CYCLE_ADD_WAIT;
FSM_STATE_CYCLE_ADD_EXTRA_TRIG: fsm_state_next = FSM_STATE_CYCLE_ADD_EXTRA_WAIT ;
FSM_STATE_CYCLE_ADD_EXTRA_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_AFTER_CYCLE_TRIG : FSM_STATE_CYCLE_ADD_EXTRA_WAIT;
FSM_STATE_AFTER_CYCLE_TRIG: fsm_state_next = FSM_STATE_AFTER_CYCLE_WAIT ;
FSM_STATE_AFTER_CYCLE_WAIT: fsm_state_next = fsm_wait_done ? fsm_state_after_cycle : FSM_STATE_AFTER_CYCLE_WAIT;
FSM_STATE_INVERT_TRIG: fsm_state_next = FSM_STATE_INVERT_WAIT ;
FSM_STATE_INVERT_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_CONVERT_TRIG : FSM_STATE_INVERT_WAIT;
FSM_STATE_CONVERT_TRIG: fsm_state_next = FSM_STATE_CONVERT_WAIT ;
FSM_STATE_CONVERT_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_CONVERT_EXTRA_TRIG : FSM_STATE_CONVERT_WAIT;
FSM_STATE_CONVERT_EXTRA_TRIG: fsm_state_next = FSM_STATE_CONVERT_EXTRA_WAIT ;
FSM_STATE_CONVERT_EXTRA_WAIT: fsm_state_next = fsm_wait_done ? FSM_STATE_DONE : FSM_STATE_CONVERT_EXTRA_WAIT;
FSM_STATE_DONE: fsm_state_next = FSM_STATE_IDLE ;
endcase
//
end
//
// Worker
//
wire worker_output_now = (fsm_state == FSM_STATE_CONVERT_EXTRA_WAIT);
ecdsa384_uop_worker uop_worker
(
.clk (clk),
.rst_n (rst_n),
.ena (worker_trig),
.rdy (worker_done),
.uop_offset (worker_offset),
.output_now (worker_output_now),
.flagz_sz (worker_flagz_sz),
.flagz_rz (worker_flagz_rz),
.flagz_e (worker_flagz_e),
.flagz_f (worker_flagz_f),
.xy_addr (rxy_addr),
.xy_dout (rxy_dout),
.x_wren (rx_wren),
.y_wren (ry_wren)
);
//
// Ready Flag Logic
//
reg rdy_reg = 1'b1;
assign rdy = rdy_reg;
always @(posedge clk or negedge rst_n)
//
if (rst_n == 1'b0) rdy_reg <= 1'b1;
else case (fsm_state)
FSM_STATE_IDLE: if (ena) rdy_reg <= 1'b0;
FSM_STATE_DONE: rdy_reg <= 1'b1;
endcase
endmodule
//------------------------------------------------------------------------------
// End-of-File
//------------------------------------------------------------------------------
