- Your destination register is 256 bits.
- Your destination register is in a different clock domain.
- Your timing constraints are wrong.
- Your power grid cannot support switching 256 registers.
Functional simulations will only catch #1.
...you know that a small random sample of the population tells you what the general population is like to a very high degree of certainty.
Statistics allows you to extrapolate results from a small sample set if, and only if, the the entire sample set follows a known statistical model.
There is no such thing as a right to the market value of one's property--which only exists in the minds of others to begin with.
I wish housing values weren't guaranteed either. Unfortunately the federal government has recently passed some extremely large spending programs designed specifically to do just that.