[sv-ac] Semantics of "calling subroutines on match of a sequence" is not well defined.

All,

a new problem (ID 0000921):

Semantics of "calling subroutines on match of a sequence" is not well 
defined.

Section 17.9: The LRM defines the syntax of " calling subroutines on
match of a sequence", however the semantic is not well defined.

In some cases, it is not clear whether a subroutine call should
happen. For example in the sequence:

sequence s1;

  ((a[*2] , $display("aa")) #1 a)

intersect

   b[*3];

endsequence

Assume that at the first 4 cycles a is high and b is low. It is not defined
whether the $display should be executed.

In other cases it is not clear how many times a subroutine should be called
in a given cycle.

For example in the sequence

sequence s2;

(
  (a #1 a)
or
  (b #1 b)
)

#1
 
(c, $display("c"));

endsequence

In case that a,b, and c are high at the first 3 cycles, it is not
clear how many times the $display should be executed.


Doron Bustan
Freescale Semiconductor, Inc.