User guide

24-88
SystemVerilog Testbench Constructs
Unidirectional Constraints
The current extension to the constraint language allows the
specification of partition points in the constraint set using the unary
function $void()or using the hard keyword in conjunction with
solve-before, improving the performance and capacity of the solver
system.
•$void()
• solve-before hard
$void(). The constraint language allows the use of built-in unary
identity function, $void(). Any valid constraint expression can be a
parameter to the $void() function.
Syntax
function return_type $void(expression);
return_type
Is the same as that of expression.
expression
Can be any valid constraint expression.
Example 24-2
constraint b1{
y inside {2,3};
x % $void(y) == 0;
}
Semantics