RISC Processor Emulation Flag Register for X86 Compatibility
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Solution Overview
Problem
Existing RISC processors face performance overhead due to simulation-based operation of 6-bit flag bits in flag registers, hindering compatibility with X86 instruction set and impacting virtual machine performance.
Innovation Solution
A RISC processor with a physical register stack, operating component, and decoder that includes an emulation flag register and flag read-write module to efficiently read, write, and modify flag bits, allowing for direct operation and branch control, mimicking the X86 instruction set's flag behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If simulation-based operation is used for flag bits in RISC processor, then compatibility with X86 instruction set is achieved, but virtual machine performance deteriorates due to overhead
Solution Approach 1:
The patent creates a physical emulation flag register that copies the structure and behavior of the X86 EFLAGS register. This physical copy enables direct hardware-level emulation of X86 flag operations, eliminating the need for software simulation and the associated performance overhead while maintaining full compatibility with X86 instruction sets on RISC architecture
Solution Approach 2:
The patent replaces the software-based simulation mechanism with a hardware-based physical register and dedicated flag operation circuits. This substitution of mechanical/software system with a hardware system provides direct flag bit manipulation capabilities, significantly improving execution speed and virtual machine performance while preserving X86 compatibility
2Productivity
If physical register stack with emulation flag register is added, then direct hardware support for X86 flag bits is provided, but device complexity increases
Solution Approach 1:
The emulation flag register is designed to serve multiple functions: it physically stores X86-style flag bits, supports direct read/write operations by the operating component, and interfaces with the decoder for instruction decoding. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity while achieving direct hardware support for flag operations
Solution Approach 2:
The patent merges the emulation flag register into the existing physical register stack structure of the RISC processor. By combining the flag storage function with the existing register infrastructure rather than creating a completely separate system, the patent minimizes structural complexity additions while providing the necessary hardware support for X86 flag bit operations
Data Source
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AI summary
The present invention discloses a RISC processor and a method of processing flag bits of a register in the RISC processor. Said RISC processor comprises a physical register stack, an operating component connected to the physical register stack and an decoder connected to the operating component; the physical register stack comprises an emulation flag register for emulating to realize flag bits of a flag register in a CISC processor; the operating component comprises a flag read-write module for reading and writing the values of the flag bits of the emulation flag register. The operating component further comprises an operating controller for performing an operation control according to the values of the flag bits of the emulation flag register when the RISC processor is in the working mode of X86 virtual machine during an operation process.