Processor Indirect Register Access via Nested Stages

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Solution Overview

Problem

Digital signal processors face limitations in performing indirect register read and write operations due to the complexity and cost of implementing such logic, which restricts flexibility in accessing values stored in registers based on the value of another register.

Innovation Solution

A method and system that enable accessing a first register based on a program instruction, obtaining a register-out value, and using it to access and store values in a second register, allowing for indirect read and write operations within the processor pipeline, leveraging an interleaved multithreading architecture to execute these operations efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If indirect register read and write operations are implemented in digital signal processors, then flexibility in accessing register values is improved, but device complexity increases

Engineering Contradiction:
Improveflexibility in accessing register valuesVSAvoidcomplexity of indirect access logic
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements indirect register access by nesting register file stages, where a first stage handles direct access and a second stage handles indirect access. The output of the first stage becomes the input for the second stage, allowing complex indirect addressing to be achieved through hierarchical organization of simpler components.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The register file is segmented into multiple independent stages (first stage and second stage), each capable of handling specific types of access operations. This segmentation allows the system to perform both direct and indirect register access simultaneously without requiring a single complex access mechanism.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If indirect register access operations are implemented, then program logic flexibility is improved, but manufacturing cost increases

Engineering Contradiction:
Improveprogram logic flexibilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Each register stage is designed with universal functionality to handle both direct and indirect access operations. The same register stage structure can be used for different access patterns, reducing the need for specialized hardware and lowering manufacturing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

By nesting simpler register stages rather than implementing a single complex indirect access mechanism, the patent reduces manufacturing cost. Each nested stage uses standardized, simpler logic that is easier and less expensive to manufacture than a monolithic complex access unit.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If indirect register read and write operations are supported, then operational flexibility is improved, but logic complexity increases

Engineering Contradiction:
Improveoperational flexibilityVSAvoidlogic complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The logic is segmented into separate control units for each register stage, with each unit handling specific aspects of register access. This segmentation simplifies the control logic within each unit while maintaining overall operational flexibility through coordinated operation of multiple units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The register file stages are designed to dynamically switch between direct and indirect access modes based on control signals. This dynamic capability allows the system to adapt to different operational requirements without requiring separate dedicated logic paths for each access type.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1861775B1Processor and method of indirect register read and write operations
Publication Date: 2016.06.15 QUALCOMM INC
  • EP1861775B1 patent drawingFigure 1
  • EP1861775B1 patent drawingFigure 2
  • EP1861775B1 patent drawingFigure 3~4

AI summary

A processor is operable to carry out a method that comprises accessing a first register based on a program instruction and obtaining a first register-out value, accessing a second register based on the first register-out value and obtaining a second register-out value, and storing the second register-out value into a third register based on the program instruction. The processor is further operable to carry out a method that comprises accessing a first register based on a program instruction and obtaining a first register-out value, accessing a second register based on the program instruction and obtaining a second register-out value, and storing the first register-out value into a third register based on the second register-out value.