//
//  Generate Clock
//
    initial
    begin
	gclock = 1;
	clock = 1;
    end

//
// Standard sim clock period.
//
    always
    begin
	clock = 1;
	#800;
	clock = 0;
	#800;
    end

//
// A one-time permanent assignment for gclock (value of gclock depends on
// gclock_enable_t and the free-running clock; if gclock_enable_t goes away,
// we hold the current value of gclock).
//
always @(clock)
    gclock = gclock_enable ? clock:gclock;