@* Syntax Questions

From: Clifford E. Cummings (cliffc@sunburst-design.com)
Date: Tue Jul 13 1999 - 10:54:04 PDT


Dear BTF -

In order to accurately complete the BNF I have a few questions.

delay_or_event_control ::=
          delay_control
        | event_control
        | repeat ( expression ) event_control
delay_control ::=
          # delay_value
        | # ( mintypmax_expression )
event_control ::=
          @ event_identifier
        | @ ( event_expression )
1999 B08> | @*
1999 B08> | @ (*)

Are the following legal and what do they mean?

um = @* a + b;
sum <= @* a & b;

Looks like redundant event controls to me (whenever a or b change, do the
respective blocking or nonblocking assignment)

Is the following legal?

um <= repeat (3) @* a + b;

Wait for three events on a or b?

Is the following legal?

repeat (3) @(posedge clk) y = a + 1; // execute y = a+1 three times on the
next three posedge clks
repeat (3) @(posedge clk); y = a + 1; // wait for three posedge clks and
then execute y = a+1
repeat (3) @(*) y = a + 1; // execute y = a+1 three times on the next
three changes on "a"??
repeat (3) @*; y = a + 1; // No wait (wasted repeat statement with @*) but
execute y = a+1 ????

Wait for three events on a or b?

- Cliff

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