Data processing apparatus and method fo operating a data processing apparatus

• US 20040193693A1
• Filed: 12/23/2003
• Published: 09/30/2004
• Est. Priority Date: 06/29/2001
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Essink, Gerben, Van Der Wolf, Pieter, Nieuwland, Andre Krijn, Gangwal, Om Prakash
• Application Number:
  US10/481,983
• Publication Number:
  US 20040193693A1
• Time in Patent Office: Days
• US Class Current: 709/213
• CPC Class Codes: G06F 2205/102 Avoiding metastability, i.e. preventing hazards, e.g. by using Gray code counters
• CPC Class Codes: G06F 5/12 Means for monitoring the fill level; Means for resolving contention, i.e. conflicts between simultaneous enqueue and dequeue operations
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A data processing apparatus according to the invention comprises at least a first (1.2) and a second processor (1.3), which processors are capable of communicating data to each other by exchanging tokens via a buffer according to a synchronization protocol. The protocol maintains synchronization information comprising at least a first and a second synchronization counter (writec, readc), which are readable by both processors. At least the first processor (1.2) is capable of modifying the first counter (writec), and at least the second processor (1.3) is capable of modifying the second counter (readc). The protocol comprises at least a first command (claim) which when issued by a processor results in a verification whether a requested number of tokens is available to said processor, and a second command (release) which results in updating one of the synchronization counters to indicate that tokens are released for use by the other processor. At least one of the processors (1.3) comprises a storage facility for locally storing an indication (Nc; writec′, readc) of the amount of tokens available to that processor, wherein issuing the first command (claim) results in a verification of the number of tokens available to said processor on the basis of said indication. A negative outcome of the verification results in updating of this indication on the basis of at least one of the synchronization counters. Issuing the second command (release) by a processor results in updating the indication in accordance with the number of tokens released to the other processor.

Claims

1. A data processing apparatus comprising at least a first and a second processor, which processors are capable of communicating data to each other by exchanging tokens via a buffer according to a synchronization protocol, which protocol maintains synchronization information comprising at least a first and a second synchronization counter, which are readable by both processors, at least the first processor being capable of modifying the first counter, and at least the second processor being capable of modifying the second counter, the protocol comprising at least a first command which when issued by a processor results in a verification whether a requested number of tokens is available to said processor, and a second command which results in updating one of the synchronization counters to indicate that tokens are released for use by the other processor,

wherein at least one of the processors comprises a storage facility for locally storing an indication of the amount of tokens available to that processor, wherein issuing the first command results in a verification of the number of tokens available to said processor on the basis of said indication,

wherein a negative outcome of said verification results in updating of this indication on the basis of at least one of the synchronization counters,

wherein issuing the second command by a processor results in updating the indication in accordance with the number of tokens released to the other processor.

2. Data processing apparatus according to claim 1, wherein the indication initially indicate that no buffer space is available.

3. Data processing apparatus according to claim 1, being arranged for updating the indication on the basis of at least one of the synchronization counters, independent of the first command.

4. Data processing apparatus according to claim 1, wherein the first synchronization counter is indicative for an amount of tokens released by the first processor and the second synchronization counter is indicative for an amount of buffer space released by the second processor.

5. Data processing apparatus according to claim 1, wherein the first synchronization counter is indicative for an amount of tokens available to the first processor and the second synchronization counter is indicative for an amount of tokens available to the second processor.

6. Data processing apparatus according to claim 1, comprising one or more further second processors, wherein each of the second processors reads the data produced by the first processor.

7. Data processing apparatus according to claim 1, wherein at least one of the processors is a general purpose processor or an application specific programmable device executing a computer program.

8. Data processing apparatus, wherein at least one of the processors is a dedicated processor.

9. Method for operating a data processing apparatus comprising at least a first and a second processor, wherein the processors communicate data to each other by exchanging tokens via a buffer according to a synchronization protocol, which protocol maintains synchronization information comprising at least a first and a second synchronization counter, which are readable by both processors, at least the first processor being capable of modifying the first counter, and at least the second processor being capable of modifying the second counter, the protocol comprising at least a first command which when issued by a processor results in verifying whether a requested number of tokens is available to said processor and/or an ownership of the requested number of tokes, and a second command which results in updating one of the synchronization counters to indicate that tokens are released for use by the other processor,

wherein at least one of the processors comprises a storage facility for locally storing an indication of the amount of tokens available to that processor, wherein issuing the first command results in a verification of the number of tokens available to said processor on the basis of said indication,

wherein a negative outcome of said verification results in updating of this indication on the basis of at least one of the synchronization counters,

wherein issuing the second command by a processor results in updating the indication in accordance with the number of tokens released to the other processor.