Ever since malloc() (and it’s other-language counterparts), software engineers have had an extra verb that is foreign to hardware engineers: “destroy.”

Both software and hardware engineers are comfortable with creating things. Software programs create objects and abstract entities; hardware engineers create hardware using software-like notations in languages like Verilog. But that’s where the similarity ends. Software engineers eventually destroy that which they create (or their environment takes care of it for them… or else they get a memory leak). Hardware engineers do not destroy anything (unless intentionally blowing a metal fuse or rupturing an oxide layer as a part of an irreversible non-volatile memory-cell programming operation).

So “destroy” is not in the hardware engineer’s vocabulary. (Except in those dark recesses perambulated only on those long weekends of work when you just can’t solve that one problem…)

This is mostly not a problem, since software and hardware engineers inhabit different worlds with different rules and different expectations. But there is a place where they come together, creating some confusion for the hardware engineer: interactive debugging during verification.

SystemVerilog consists of much more than some synthesizable set of constructs. It is rife with classes from which arise objects, and objects can come and go. This is obvious to a software engineer, but for a hardware engineer in the middle of an interactive debug session, it can be the height of frustration: “I know I saw it, it was RIGHT THERE! And now it’s gone! What the…”

This was pointed out by Cadence when we were discussing the recent upgrades to their Incisive platform. The verification engineers that set up the testbenches are generally conversant in the concepts of both hardware and software, but the designer doing debug may get tripped up by this. Their point being, well, that hardware engineers need to remember that the testbench environment isn’t static in the way that the actual design is: they must incorporate “destroy” into their vocabulary.