can increase simulation run time while running modelsim?

I am not an expert with ModelSim but I feel this is true with testbenches: The testbench is run out as a script until all its input-output verifications are complete. As such, the run length of a testbench cannot be changed at ModelSim runtime and can only be done by increasing the input-output test vectors in the testbench right at the start. I hope I am able to get that through. I have experienced that ModelSim-XE simulates testbenches of a few microsecond duration quite quickly. So you are probably simulating a duration of a few seconds or more and hence the hour-long running time. You may hence also concetrate on finding ways to simulate only the time interval of interest (I don't know how to do that, though). And yes, if test fixtures are something quite different than testbenches, just ignore this post.

run 10ms

and it'll continue the simulation, from where it left off, for another

-a