XP Running on a 486 CPU
The user faced compatibility issues installing Windows XP SP3 on a 486 CPU due to the cmpxchg8b opcode. They discussed modifying assembly code in ntoskrnl.exe for 486 CPU compatibility, sharing insights and solutions.
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The user attempted to install Windows XP SP3 on a Shuttle Hot 433 board with a 486 CPU but encountered an error message stating that the CPU did not support the hex opcode cmpxchg8b, preventing the installation. They explored replacing this opcode with a series of instructions understandable by the 486 CPU to enable XP installation. The user shared their findings on modifying the ExInterlockedFlushSList function in ntoskrnl.exe to make it compatible with the 486 CPU. They discussed the challenges faced in replacing the cmpxchg8b opcode and shared their attempts at creating a suitable replacement sequence. Additionally, another user suggested looking into Vogons forums for similar experiments with Windows XP on 486 CPUs. The discussion delved into the intricacies of assembly code modifications required for compatibility with older CPUs like the 486. The users shared insights and code snippets aimed at addressing the limitations posed by the cmpxchg8b opcode and ensuring proper functionality on the 486 CPU architecture.
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