Repetition Operators

property p;
  @(posedge clk) a |-> ##1 b ##1 b ##1 b;
endproperty
a: assert property(p);

The above property checks that, if the signal “a” is high on given posedge of the clock, the signal “b” should be high for 3 consecutive clock cycles.

The Consecutive repetition operator is used to specify that a signal or a sequence will match continuously for the number of clocks specified.

Syntax

signal [*n] or sequence [*n]

"n" is the number of repetitions.

with repetition operator above sequence can be re-written as,

property p;
  @(posedge clk) a |-> ##1 b[*3];
endproperty
a: assert property(p);

Click to execute on   

go to repetition

The go-to repetition operator is used to specify that a signal will match the number of times specified not necessarily on continuous clock cycles.

signal [->n]

property p;
  @(posedge clk) a |-> ##1 b[->3] ##1 c;
endproperty
a: assert property(p);

Click to execute on   

The above property checks that, if the signal “a” is high on given posedge of the clock, the signal “b” should be high for 3 clock cycles followed by “c” should be high after ”b” is high for the third time.

Nonconsecutive repetition

This is very similar to “go to” repetition except that it does not require that the last match on the signal repetition happens in the clock cycle before the end of the entire sequence matching.

signal [=n]

Only expressions are allowed to repeat in “go to” and “nonconsecutive” repetitions. Sequences are not allowed.

❮ Previous Next ❯