Pointer register indirectly addressing a second register in the processor core of a digital processor

• US 6,052,766 A
• Filed: 08/18/1998
• Issued: 04/18/2000
• Est. Priority Date: 07/07/1998
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Betker, Michael R., Lemmon, Frank, Whalen, Shaun P., Fernando, John S.
• Primary Examiner(s): An, Meng-Ai T.
• Assistant Examiner(s): EL HADY, NABIL M
• Application Number:
  US09/135,605
• Time in Patent Office: 609 Days
• Field of Search: 395/800.23, 711/202, 711/211, 712/217, 712/16
• US Class Current: 711/200
• CPC Class Codes: G06F 9/30098 Register arrangements

Abstract

A first register stores a value that can be used as a pointer to indirectly address a second register. The first register is referred to as a pointer register and the pointer as a register pointer. The second register may be a conventional register that stores a conventional register value (i.e., a data value or a pointer to a data value stored in external memory) or another pointer register. In certain embodiments, a pointer register can also be used to store conventional register values. Pointer registers of the present invention can be used to implement efficiently certain types of digital processing, such as circular buffers, vector processing, convolutional processing, and partitioned processing, using data in registers rather than memory.

Claims

1. An integrated circuit having a digital processor comprising a first register and a second register, wherein the first and second registers are located inside a processor core of the digital processor and the first register is adapted to store a pointer corresponding directly to a register address of the second register without having to be converted through a memory space corresponding to memory located outside of the processor core, such that the second register can be indirectly addressed using the pointer in the first register, wherein:

the first register is adapted to selectively store the pointer, a data value, or a memory address in the memory space; and

the second register is adapted to selectively store a data value or a memory address in the memory space.

2. The invention of claim 1, wherein the first register is a pointer register and the second register is part of a register file.

3. The invention of claim 2, wherein the pointer register is implemented separate from the register file.

4. The invention of claim 2, wherein the pointer register is implemented as part of the register file.

5. The invention of claim 2, wherein the pointer register is addressed using a name space identical to a name space for the register file.

6. The invention of claim 2, wherein the pointer register is addressed using a name space different from a name space for the register file.

7. The invention of claim 2, further comprising an extended register file having one or more additional registers that can be accessed via the pointer register.

8. The invention of claim 1, wherein the first and second registers are pointer registers and the second register is adapted to store a pointer corresponding to a register address of a third register, such that the third register can be indirectly addressed using the pointer in the first register and the pointer in the second register.

9. The invention of claim 1, wherein the digital processor further comprises a first multiplexer configured to receive a first input corresponding to a register address from an instruction and a second input corresponding to the pointer from the first register and to generate an output corresponding to the register address of the second register.

10. The invention of claim 9, wherein the digital processor further comprises a second multiplexer configured to receive a first input corresponding to a value stored in the second register and a second input corresponding to a value stored in the first register and to generate an output corresponding to a data read instruction.

11. The invention of claim 9, wherein the digital processor further comprises a first demultiplexer configured to receive an input corresponding to a value to be written into one of the first and second registers and to selectively generate one of a first output configured to pass the value to be stored to the first register and a second output configured to pass the value to be stored to the second register.

12. The invention of claim 9, wherein the first multiplexer is selectively controlled based in part on a logical flag that determines whether or not to use the pointer stored in the first register to address the second register.

13. The invention of claim 9, wherein the digital processor further comprises a third register adapted to store a pointer corresponding to the register address of the second register, such that the second register can be indirectly addressed using the pointer in the third register.

14. The invention of claim 13, wherein the digital processor further comprises a second multiplexer configured to receive a first input corresponding to the pointer from the first register and a second input corresponding to the pointer from the third register and to generate an output corresponding to the second input to the first multiplexer.

15. The invention of claim 1, wherein:

the second register is configured as part of a circular buffer;

the first register is configured to store a stride value, a begin value, and an end value for the circular buffer; and

the digital processor further comprises a pointer update function adapted to update the pointer in the first register using the stride, begin, and end values to sequentially point to different parts of the circular buffer.

16. The invention of claim 15, wherein the circular buffer stores packed data processed by a partitioned functional unit.

17. The invention of claim 1, wherein the digital processor further comprises a third register and a fourth register, wherein the third register is adapted to store a pointer corresponding to a register address of the fourth register, such that the fourth register can be indirectly addressed using the pointer in the third register.

18. The invention of claim 17, wherein:

the second register is configured as part of a first circular buffer;

the first register is configured to store a stride value, a begin value, and an end value for the first circular buffer;

the fourth register is configured as part of a second circular buffer;

the third register is configured to store a stride value, a begin value, and an end value for the second circular buffer; and

the digital processor further comprises;

a first pointer update function adapted to update the pointer in the first register using the stride, begin, and end values in the first register to sequentially point to different parts of the first circular buffer; and

a second pointer update function adapted to update the pointer in the third register using the stride, begin, and end values in the third register to sequentially point to different parts of the second circular buffer.

19. The invention of claim 18, wherein:

the second and fourth registers are part of a register file having at least two access ports; and

control of the first circular buffer is independent of control of the second circular buffer.