Register Mapping in Emulation of Target System on Host
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Solution Overview
Problem
Emulating a target system with larger registers on a host system with smaller registers, such as emulating a 128-bit CPU on a 64-bit cell processor, results in inefficiencies due to the mismatch in register sizes, leading to slower execution speeds and potential instruction blocking.
Innovation Solution
Dynamically mapping target system registers to host system registers based on usage statistics, with frequently used registers directly mapped and less frequently used registers dynamically mapped to a pool of registers, allowing for rotation to prevent instruction blocking and efficient use of resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If target system registers are directly mapped to host system registers, then register access speed is improved, but register mapping complexity increases when register sizes differ
Solution Approach 1:
The patent segments register mapping into two distinct approaches: direct mapping for frequently accessed registers and dynamic mapping for less frequently accessed registers. This segmentation allows the system to maintain simple direct mappings for hot registers while using more flexible dynamic mappings for cold registers, thereby reducing overall mapping complexity while preserving fast access for critical operations.
Solution Approach 2:
The patent introduces dynamic register mapping that adapts to runtime conditions, allowing the mapping strategy to change based on actual register usage patterns. This dynamic approach enables the system to optimize between direct mapping simplicity and dynamic mapping flexibility according to workload characteristics, resolving the contradiction between mapping simplicity and adaptability.
2Adaptability or versatility
If all target registers are dynamically mapped to host registers, then adaptability to different register sizes is improved, but execution speed decreases due to mapping overhead
Solution Approach 1:
The patent divides registers into two subsets based on usage frequency: frequently accessed registers that use direct mapping for optimal speed, and less frequently accessed registers that use dynamic mapping for adaptability. This segmentation ensures that the performance penalty of dynamic mapping is minimized while maintaining the adaptability benefits where needed.
Solution Approach 2:
The patent applies different mapping qualities to different registers based on their access patterns. Hot registers receive the high-performance direct mapping treatment, while cold registers receive the adaptable dynamic mapping treatment. This local differentiation optimizes the balance between speed and adaptability for each register based on its specific characteristics.
3Device complexity
If register mapping is static, then mapping simplicity is maintained, but instruction blocking increases due to register availability constraints
Solution Approach 1:
The patent implements dynamic register mapping that can adapt to changing register availability conditions during instruction execution. This dynamic capability allows the system to prevent instruction blocking by finding available host registers even when direct mappings are exhausted or become unavailable, thereby improving instruction execution reliability without completely abandoning mapping simplicity.
Solution Approach 2:
The patent introduces a dynamic mapping mechanism as an intermediary between the static direct mapping and the runtime register availability conditions. This intermediary layer resolves conflicts and prevents blocking by mediating between what is statically mapped and what is actually available at runtime, ensuring reliable instruction execution.
Data Source
AI summary
Methods and systems for register mapping in emulation of a target system on a host system are disclosed. Statistics for use of a set of registers of a target system processor are determined. Based on the statistics a first subset of the target system registers, including one or more most commonly used registers is determined. The registers in the first subset are directly mapped to a first group of registers of a host system processor. A second subset of the set of target system registers is dynamically mapped to a second group of registers of the host system processor.