A random number generator circuit includes a primary circuit configured to generate a value within a first range and a secondary circuit configured to generate a value within a second range. A detector circuit detects whether or not the value from the primary circuit is within the desired output range for the random number generator circuit, and selects either the value from the primary circuit or the value from the secondary circuit in response. The second range is the desired output range and the first range encompasses the second range. In one embodiment, the primary circuit has complex harmonics but may generate values outside the desired range. The secondary circuit may have less complex harmonics, but may generate values only within the desired range. In one implementation, the random number generator circuit is used to generate a replacement way for a cache.
A packet processing system may include a processor, a cache, a memory controller, and at least one packet interface circuit integrated into a single integrated circuit. In one embodiment (which may be used in integrated or non-integrated systems), the packet interface circuit is configured to cause allocation in the cache of a portion of a received packet. In one embodiment (which may be used in integrated or non-integrated systems), the memory controller may be configured to selectively block memory transactions. Particularly, the memory controller may implement at least two block signals, one for the packet interface circuit and one for other devices. The block signals may be used to control the initiation of memory transactions when the memory controller's input queue is approaching fullness.
