VHDL language construct synthesis

The answer is usually combinatorial, but the registers would come if you placed the function/procedure inside a clocked process.

If there any reason you want to use functions/procedures? Using these does not allow any pipelining in the function/procedure, so you're taking away the greatest power to increase your FMax.

Anyways, procedures are fairly redundant in synthesisable code because of the fact you can only really scribe combinatorial logic in them. THey are way more useful in testbenches (where you can make one procedure emulate an entire bus transaction).