>So, do the routines that I have developed over time and use regularly (some of the logic goes *way* back) remain my intellectual property even if embedded in something that I have written as an employee?

I don't think anyone has suggested anything of the kind. In message after message, I've seen it stated that if you develop code as an employee, it belongs to the employer. If that's not the case, it's yours.

However, if you develop general-purpose code as an employee (and who doesn't generate new general-purpose code on each and every project?), it belongs to the employer. That's a bit of a problem, for which the only solution is not to be an employee. :)