Debug Circuit Instruction Set Mode Comparison
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Solution Overview
Problem
Debugging complex code on modern processors is challenging due to their intricate pipelined architecture and multiple instruction set operating modes, as existing debug circuits do not consider the processor's instruction set operating mode when triggering breakpoints or initiating traces, making it difficult to diagnose errors caused by incorrect mode transitions.
Innovation Solution
A debug circuit that compares the current instruction set operating mode with a target mode during execution, allowing programmers to set breakpoints or initiate traces within specific address ranges, thereby detecting and addressing mode mismatches that lead to errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing debug circuits are used without considering instruction set operating mode, then the debug circuit structure remains simple, but the ability to accurately detect mode mismatches and debugging accuracy deteriorates
Solution Approach 1:
The patent merges the instruction set operating mode detection functionality with the existing debug circuit structure. The debug circuit integrates mode mismatch detection by combining the current mode indicator from the processor status with the breakpoint trigger logic, allowing accurate detection of mode mismatches without requiring a completely separate detection system.
Solution Approach 2:
The debug circuit is designed to perform multiple functions: it handles traditional breakpoint triggering based on instruction addresses while simultaneously monitoring instruction set operating modes. This multi-functional approach allows the same circuit to detect both address-based breakpoints and mode-based anomalies, improving debugging accuracy without proportionally increasing complexity.
2Adaptability or versatility
If the processor supports multiple instruction set operating modes for versatility, then the processor can execute different instruction sets, but the difficulty of detecting and measuring mode mismatches increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the current instruction set operating mode through the mode indicator in the processor status and comparing it against the expected mode. This feedback mechanism provides real-time detection of mode mismatches, allowing the debug circuit to trigger alerts or halt execution when the actual mode differs from the expected mode, thereby solving the detection difficulty.
Solution Approach 2:
The patent introduces an intermediary mechanism - the debug circuit with mode comparison logic - that mediates between the processor's multiple instruction set capabilities and the debugging requirements. This intermediary layer translates the internal processor mode state into detectable signals for debugging purposes, making mode mismatches visible and measurable without affecting the processor's normal versatile operation.
3Ease of operation
If debug tools are added to assist with debugging complex code, then debugging capability improves, but the processor performance and power consumption are impacted
Solution Approach 1:
The patent applies partial action by implementing debug functionality only when needed. The mode comparison and breakpoint triggering occur selectively based on the current execution context and debugger control signals, rather than continuously monitoring and interfering with every instruction. This partial engagement maintains debugging capability while minimizing impact on overall processor performance and power consumption.
Data Source
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AI summary
A processor is operative to execute two or more instruction sets, each in a different instruction set operating mode. As each instruction is executed, debug circuit comparison the current instruction set operating mode to a target instruction set operating mode sent by a programmer, and outputs an alert or indication in they match. The alert or indication may additionally be dependent upon the instruction address following within a predetermined target address range. The alert or indication may comprise a breakpoint signal that halts execution and/or it is output as an external signal of the processor. The instruction address at which the processor detects a match in the instruction set operating modes may additionally be output. Additionally or alternatively, the alert or indication may comprise starting or stopping a trace operation, causing an exception, or any other known debugger function.