Predictive Register Renaming for Data Type-Specific Register Clusters

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Solution Overview

Problem

Modern processors face inefficiencies in power consumption and circuit delays due to the handling of multiple data types in unified physical register files, particularly in out-of-order execution systems, where write-after-write and write-after-read hazards are not adequately addressed by conventional register renaming techniques.

Innovation Solution

Implementing a processor architecture with separate clusters for different data types, using register renaming based on data type prediction to optimize physical storage and computation, and incorporating an alternate datapath for efficient handling of mispredictions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a unified physical register file is used to hold different data types, then register capacity and versatility are improved, but power consumption and circuit delays increase due to routing through various functional units

Engineering Contradiction:

Improveregister capacityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The unified physical register file is divided into multiple data type-specific clusters (e.g., integer cluster, floating-point cluster, vector cluster). Each cluster contains physical registers dedicated to a specific data type and is paired with corresponding functional units, eliminating the need to route different data types through a single unified register file and reducing power consumption.

Inventive Principle:

Principle #1Segmentation

2Reliability

If physical register renaming is used to remove write-after-write and write-after-read hazards, then execution correctness is improved, but power consumption increases due to additional routing operations

Engineering Contradiction:

Improveexecution correctnessVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The register renaming process is segmented by data type, with separate renaming tables and physical register allocations for different data types. This allows the system to maintain execution correctness through renaming while reducing power consumption by avoiding cross-type routing operations and optimizing the renaming process for specific data type clusters.

Inventive Principle:

Principle #1Segmentation

3Use of energy by moving object

If separate clusters for different data types are implemented, then power consumption and circuit delays are reduced, but device complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddevice complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The register renaming circuit is designed with multi-functionality to handle different data types efficiently. It includes a data type predictor that anticipates the type of data being operated on and pre-configures the appropriate cluster, reducing the need for complex real-time routing decisions and mitigating the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Speed

If data type prediction is used for register renaming, then execution speed is improved, but reliability decreases when predictions are incorrect

Engineering Contradiction:

Improveexecution speedVSAvoidprediction accuracy

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The data type predictor performs preliminary action by predicting the data type before the actual register renaming occurs. This allows the system to pre-allocate and prepare the appropriate physical registers in the predicted cluster, improving execution speed. The predictor uses heuristics based on instruction patterns and historical data to make accurate predictions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The data type predictor acts as an intermediary between the instruction decoder and the register renaming circuit. It analyzes the instruction and provides type information that guides the renaming process, enabling faster execution while maintaining reliability through intelligent prediction algorithms that consider program context and data flow patterns.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260064426A1Technologies for prediction-based register renaming

Publication Date: 2026.03.05 SIFIVE INC

AI summary

Systems and methods are disclosed for register renaming. For example, an integrated circuit is described that includes a first cluster including a first set of physical registers and a first execution resource circuit, wherein the inputs for operations of the first execution resource circuit are of a first data type; a second cluster including a second set of physical registers and a second execution resource circuit, wherein the inputs for operations of the second execution resource circuit are of a second data type that is different than the first data type; and a register renaming circuit configured to: determine a data type prediction for a result of a first instruction that will be mapped to a first logical register; and, based on the data type prediction matching the first data type, rename the first logical register to be mapped to a physical register of the first set of physical registers.