Higher level: Behavioural or Logical ?

There are two primary, high-level styles we can consider, and we can also consider blends of them:

• Behavioural Expression: Using imperative software-like code, where threads have stacks and pass between modules, and so on...
• Declarative/Logical Expression: Constraining assertions about the allowable behaviour are given, but any ordering constraints are implicit.

There is a related subject of back-end synthesis: netlist generation, re-encoding and re-pipelining to meet timing closure and power budgets.