verilator/test_regress/t/t_cover_fsm_reset_multi.v

53 lines
1.1 KiB
Systemverilog

// DESCRIPTION: Verilator: FSM coverage multi-reset assignment warning test
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2026 Wilson Snyder
// SPDX-License-Identifier: CC0-1.0
module t (
input clk
);
typedef enum logic [1:0] {
S0 = 2'd0,
S1 = 2'd1,
S2 = 2'd2
} state_t;
logic rst;
integer cyc;
state_t state /*verilator fsm_reset_arc*/;
initial begin
rst = 1'b1;
cyc = 0;
end
always @(posedge clk) begin
cyc <= cyc + 1;
if (cyc == 1) rst <= 1'b0;
if (cyc == 5) begin
$write("*-* All Finished *-*\n");
$finish;
end
end
// This reset block is intentionally non-idiomatic. Multiple assignments to
// the FSM state variable in the reset branch should warn and be ignored for
// reset-arc extraction rather than inventing multiple reset transitions.
always_ff @(posedge clk) begin
if (rst) begin
state <= S0;
state <= S1;
end
else begin
case (state)
S0: state <= S2;
S1: state <= S2;
default: state <= S2;
endcase
end
end
endmodule