Architecture for high performance management of multiple circular FIFO storage means

A method of generating signals useful in a queue manager for managing multiple circular FIFO storage means in handling incoming/outgoing data in a data communication system comprising the steps of:

• (a) providing to a first calculating means a selected pointer address in the circular FIFO storage means;
• (b) providing as a first output from the first calculating means an incremented selected pointer address;
• (c) providing to the first calculating means a base and size signal and providing as a second output signal a queue limit signal or the top location of a queue;
• (d) providing to a second calculating means a read pointer signal, a write pointer signal, a wrapped signal, and a memory access signal to generate a queue empty signal from the second calculating means;
• (e) providing as inputs to a third calculating means a threshold signal, a write pointer and a read pointer signal to generate as an output an at/above threshold signal;
• and
• (f) providing as an input to a logic means a data signal from each queue and generating as output signals a queue full or queue almost full signal, the signals generated in steps (c)-(f) used by the queue manager in managing incoming/outgoing data in the data communication system.

In a data communications system handling packet data and multimedia data transferred in either direction between a host bus and a network, a queue manager for managing multiple circular FIFO queue storage means included in the system, comprising:

• a programmable parameter RAM having as programmable parameters (i) a base pointer for each queue storage means identifying the starting location in the storage means;
• (ii) queue size or quantity of data;
• (iii) a threshold value indicative of when data can be transferred out of a queue;
• an "almost full" control indication of the amount of space or room left in a queue and used to set an "almost full" status line;
• (iv) a read pointer initially set to the base pointer;
• and (v) a write pointer initially set to the base pointer;
• computation logic exercising the programmable parameters to generate control signals used to update status bits for a queue being serviced by the queue manager;
• and status means coupled to the computation logic for receiving an "empty", "full", "wrapped", "almost full", and threshold signals used in receiving data from or sending data to the multiple circular FIFO queue storage means.

In a data communications system handling packet data and multimedia data transferred in either direction between a host bus and a network, a queue manager for managing multiple circular FIFO queue storage means included in the system, comprising:

• a priority control circuit responsive to a packet data source/sink and an isochronous data source/sink for selecting the data having the highest priority and providing an output to a programmable parameter RAM indicating a winning queue for storing the data;
• a programmable parameter RAM providing a plurality of parameters descriptive of the winning queue;
• computation logic receiving the parameters from the programmable parameter RAM and calculating the space or room available in the winning queue for storing the data having the highest priority;
• and
• status means coupled to the computation logic for providing signals to an application running in the system for handling data to and from the multiple storage queues.

In a data communications system handling packet data and multimedia data transferred in either direction between a host bus and a network, a queue manager for managing data transferred among a host interface, a network interface and a storage interface including multiple queue storage means, comprising:

• a programmable parameter RAM for generating signals indicative of the data storage status of each queue included in the storage means;
• computation logic coupled to the progarammable parameter RAM for receiving signal descriptive of a queue selected for storing data;
• the computation logic generating computed signals determining when a queue is "full", "empty", "almost full", or "at/above threshold";
• and
• status means for receiving the computed signals for controlling an application running in the system to receive data from or sending data to a multiple queue storage means.

In a data communications system handling packet data and multimedia data transferred in either direction between a host bus and a network bus, a queue manager for managing the transfer of data among a plurality of interfaces coupled to the host, the network and a storage means including multiple queues, comprising the steps of:

• (a) reading a word out of the storage interface comprising the steps (i) writing the corresponding queue number into a request queue for a word to be passed to a destination interface;
• (ii) transferring the data word to the destination interface if the corresponding queue is "empty" and if there is room in a destination interface queue;
• (iii) storing the word in a local storage queue if the destination interface queue is "full" or if the corresponding queue and local storage is "empty";
• and (iv) asserting an acknowledge signal to a request pool when the request to service or if the request cannot be serviced due to special conditions such as queue overflow or queue disabled;
• (b) writing a word into a host or network interface comprising the steps of:
• (i) operating a direct transfer between the interfaces via asserting a "load" line and appropriate "close queue NUM" line to the destination interface independently of a request being presented by the interfaces;
• (ii) writing the corresponding queue number into a request pool for an interface that is transmitting a word to another device;
• and
• (c) servicing the request if the corresponding queue in local storage is "not empty" and if the interface data is "not full";
• asserting an acknowledge signal when the request at the top of the pool corresponds to local storage that is "empty" or if the interface data queue is "full" or if the queue has been "disabled".