The need for BUG()


During code development we really need assertions
We need to verify values are as expected
Mishaps happens, and they need to be notified

Unfortunately, the assert code takes quite some space
Besides the conditional, you need to pass __FILE__ etc
You call printf and panic, with arguments (or __assert)

This can be an issue in hot code paths
Assert can be conditional (e.g.: CONFIG_ASSERT)
But sometimes you want to keep the check in production too

So we can use the undefined instruction handler
One instruction (two bytes in thumb code)
And an handler that looks up which asertion it was