CPUID Deprecation Bit Segmentation for Legacy Feature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The CPUID instruction fails to provide clear indication of deprecated features, leading to potential support for legacy functionalities even when they should be disabled, and its fused values make it difficult to operate in both primary and secondary modes, especially in scenarios where legacy software needs to be deprecated.
Innovation Solution
The proposed solution involves enhancing the CPUID functionality to explicitly indicate deprecated features and support for secondary execution modes, allowing the processor to deprecate certain features and provide explicit indications of legacy feature disablement, enabling the processor to operate efficiently in both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CPUID returns fused values indicating feature availability, then the processor can maintain backward compatibility with legacy software, but it cannot clearly indicate deprecated features leading to unnecessary resource allocation
Solution Approach 1:
The patent segments the CPUID feature indication into multiple independent bits: fused feature values (indicating availability) and deprecation bits (indicating deprecated status). This segmentation allows the system to simultaneously provide backward compatibility information and deprecation warnings without conflict, resolving the contradiction between maintaining legacy support and clearly indicating deprecated features.
Solution Approach 2:
The patent introduces deprecation bits as an intermediary mechanism between the fused feature values and the software. These intermediary bits carry additional information about feature deprecation status without interfering with the existing fused value system, enabling clear communication of deprecation while preserving backward compatibility.
2Stability of the object's composition
If CPUID values are fused to indicate feature availability, then legacy software can continue to operate, but it becomes difficult to operate in both primary and secondary modes with different feature sets
Solution Approach 1:
The patent segments feature indication into availability indicators (fused values) and status indicators (deprecation bits), allowing the processor to maintain stable feature availability information while adapting to different operational modes through the deprecation bit field. This enables clear distinction between features that are available versus those that are deprecated in secondary mode.
Solution Approach 2:
The patent makes the CPUID feature indication dynamic by allowing software to query deprecation bits and adapt its behavior accordingly. In primary mode, software can utilize all available features, while in secondary mode, software can detect deprecated features and adjust operations, enabling flexible multi-mode operation while maintaining stable feature availability information.
3Device complexity
If CPUID does not explicitly indicate deprecated features, then the instruction structure remains simple, but it fails to prevent support for legacy functionalities that should be disabled
Solution Approach 1:
The patent extracts deprecation information into separate deprecation bits within the CPUID response, distinct from the fused feature values. This extraction allows the system to maintain the simple fused value structure for feature availability while adding explicit deprecation indication through the separated deprecation bits, preventing support for legacy functionalities that should be disabled.
Solution Approach 2:
The deprecation bits serve as an intermediary layer between the simple CPUID structure and the requirement for legacy feature disablement. This intermediary mechanism provides explicit deprecation information without fundamentally altering the existing CPUID structure, maintaining simplicity while enabling reliable legacy feature management.
Data Source
AI summary
Techniques for CPUID are described. In some examples, a CPUID instruction is to include at least one field for an opcode, the opcode to indicate execution circuitry is to return processor identification and feature information determined by input into a first register and a second register, wherein the processor identification and feature information is to include an indication of an availability of a second execution mode that at least deprecates features of a first execution.