How To Validate Type-Casting In OVM-e Print
User Rating: / 0
PoorBest 
Thursday, 24 December 2009 16:37

Before type-casting an e variable ("as_a"), we often want to check the validity of the operation (this is quite similar in concept to $cast in SystenVerilog). The reason is simple, in case the casting operation failed we would end up with a fatal error at run-time that otherwise could have been avoided. But how?

 

Here's one elegant way to do it:

type ttt: [E1=3, E2=10];
extend sys {
 run() is also {
 var x: byte = 3; // try x=7 too
  if x.as_a(ttt) in all_values(ttt) then { out( *** X IS IN RANGE *** ) };
 };
 };

In this small example we were trying to convert (type-cast) x from byte to ttt. The method all_values() returns a list of all possible scalar types (in our case - for type ttt). Try this code with x=3 and with x=7 and see what happens.

 

 
More articles :

» Using Constrained-Random Verification with Legacy Testbenches

One of SystemVerilog's noticeable features is that it is basically a "design language" that has been extended with verification capabilities. This might be an advantage or not, depending on who you're asking, but obviously, if you only want to use a...

» Who Wants To Be A Verifier?

Are you looking for a job in verification? Are you pursuing a career in verification? Congratulations! There a few things you might want to consider about your prospective employer before you sign the contract. In today's important article we'll try...

» The Big Picture

Great verification engineers know the secret - if they want to be successful they must also understand the essence of the entire chip design flow, from concept to working samples. Here are some great videos that will help you see the big picture a...

» Debug Like The Pro's

You’ve developed a verification environment, hooked up the DUT, written a bunch of tests and alas! Simulations start to fail So just before you dive in, Think Verification’s tips department recommends the following:

» AutoDup: Create Test Variants Quickly (Free Utility)

Coverage driven verification has a big advantage – you can write a single test, and let run it several times with random seeds. Each run will generate a slightly different scenario – depending on the nature of the constraints you provided....