COMMAND NAME:

        CLOCK

USAGE:
        CLOCK [{ON | OFF}]

        This command turns the clocks on and off.  Clock ON 
        turns on the clocks; Clock OFF turns off the clocks.
        With no argument, Clock reports the ON/OFF state of 
        the clocks.  When clocks are turned off, the clock 
        generator primitives are disabled and the values of 
        clock signals stop changing.  When clocks are turned 
        on, at the start of the next simulation all clocks 
        are re-evaluated, and all clock values are immediately 
        set to their correct instantaneous values.

