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// DESCRIPTION: Verilator: Verilog Test module
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2008 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0
module t (/*AUTOARG*/
// Inputs
clk
);
input clk;
integer cyc = 0;
reg [63:0] crc;
reg [63:0] sum;
reg reset;
/*AUTOWIRE*/
// Beginning of automatic wires (for undeclared instantiated-module outputs)
wire myevent; // From test of Test.v
wire myevent_pending; // From test of Test.v
wire [1:0] state; // From test of Test.v
// End of automatics
Test test (/*AUTOINST*/
// Outputs
.state (state[1:0]),
.myevent (myevent),
.myevent_pending (myevent_pending),
// Inputs
.clk (clk),
.reset (reset));
// Aggregate outputs into a single result vector
wire [63:0] result = {60'h0, myevent_pending,myevent,state};
// Test loop
always @ (posedge clk) begin
`ifdef TEST_VERBOSE
$write("[%0t] cyc==%0d crc=%x result=%x me=%0x mep=%x\n", $time, cyc, crc, result, myevent, myevent_pending);
`endif
cyc <= cyc + 1;
crc <= {crc[62:0], crc[63] ^ crc[2] ^ crc[0]};
sum <= result ^ {sum[62:0], sum[63] ^ sum[2] ^ sum[0]};
reset <= (cyc<2);
if (cyc==0) begin
// Setup
crc <= 64'h5aef0c8d_d70a4497;
sum <= 64'h0;
end
else if (cyc<90) begin
end
else if (cyc==99) begin
$write("[%0t] cyc==%0d crc=%x sum=%x\n", $time, cyc, crc, sum);
if (crc !== 64'hc77bb9b3784ea091) $stop;
// What checksum will we end up with (above print should match)
`define EXPECTED_SUM 64'h4e93a74bd97b25ef
if (sum !== `EXPECTED_SUM) $stop;
$write("*-* All Finished *-*\n");
$finish;
end
end
endmodule
module Test (/*AUTOARG*/
// Outputs
state, myevent, myevent_pending,
// Inputs
clk, reset
);
input clk;
input reset;
output [1:0] state;
output myevent;
output myevent_pending;
reg [5:0] count = 0;
always @ (posedge clk)
if (reset) count <= 0;
else count <= count + 1;
reg myevent = 1'b0;
always @ (posedge clk)
myevent <= (count == 6'd27);
reg myevent_done;
reg hickup_ready;
reg hickup_done;
localparam STATE_ZERO = 0;
localparam STATE_ONE = 1;
localparam STATE_TWO = 2;
reg [1:0] state = STATE_ZERO;
reg state_start_myevent = 1'b0;
reg state_start_hickup = 1'b0;
reg myevent_pending = 1'b0;
always @ (posedge clk) begin
state <= state;
myevent_pending <= myevent_pending || myevent;
state_start_myevent <= 1'b0;
state_start_hickup <= 1'b0;
case (state)
STATE_ZERO:
if (myevent_pending) begin
state <= STATE_ONE;
myevent_pending <= 1'b0;
state_start_myevent <= 1'b1;
end else if (hickup_ready) begin
state <= STATE_TWO;
state_start_hickup <= 1'b1;
end
STATE_ONE:
if (myevent_done)
state <= STATE_ZERO;
STATE_TWO:
if (hickup_done)
state <= STATE_ZERO;
default:
; /* do nothing */
endcase
end
reg [3:0] myevent_count = 0;
always @ (posedge clk)
if (state_start_myevent)
myevent_count <= 9;
else if (myevent_count > 0)
myevent_count <= myevent_count - 1;
initial myevent_done = 1'b0;
always @ (posedge clk)
myevent_done <= (myevent_count == 0);
reg [4:0] hickup_backlog = 2;
always @ (posedge clk)
if (state_start_myevent)
hickup_backlog <= hickup_backlog - 1;
else if (state_start_hickup)
hickup_backlog <= hickup_backlog + 1;
initial hickup_ready = 1'b1;
always @ (posedge clk)
hickup_ready <= (hickup_backlog < 3);
reg [3:0] hickup_count = 0;
always @ (posedge clk)
if (state_start_hickup)
hickup_count <= 10;
else if (hickup_count > 0)
hickup_count <= hickup_count - 1;
initial hickup_done = 1'b0;
always @ (posedge clk)
hickup_done <= (hickup_count == 1);
endmodule
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