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Diffstat (limited to 'tests/sva/counter.sv')
-rw-r--r-- | tests/sva/counter.sv | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/tests/sva/counter.sv b/tests/sva/counter.sv new file mode 100644 index 00000000..4f949115 --- /dev/null +++ b/tests/sva/counter.sv @@ -0,0 +1,30 @@ +module top (input clk, reset, up, down, output reg [7:0] cnt); + always @(posedge clk) begin + if (reset) + cnt <= 0; + else if (up) + cnt <= cnt + 1; + else if (down) + cnt <= cnt - 1; + end + + default clocking @(posedge clk); endclocking + default disable iff (reset); + + assert property (up |=> cnt == $past(cnt) + 8'd 1); + assert property (up [*2] |=> cnt == $past(cnt, 2) + 8'd 2); + assert property (up ##1 up |=> cnt == $past(cnt, 2) + 8'd 2); + +`ifndef FAIL + assume property (down |-> !up); +`endif + assert property (up ##1 down |=> cnt == $past(cnt, 2)); + assert property (down |=> cnt == $past(cnt) - 8'd 1); + + property down_n(n); + down [*n] |=> cnt == $past(cnt, n) - n; + endproperty + + assert property (down_n(8'd 3)); + assert property (down_n(8'd 5)); +endmodule |