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Instruction general - CPUID—CPU Identification

Provides processor identification information in registers EAX, EBX, ECX, and EDX. This information identifies Intel as the vendor, gives the family, model, and stepping of processor, feature information, and cache information. An input value loaded into the EAX register determines what information is returned. The CPUID instruction can be executed at any privilege level to serialize instruction execution. Serializing instruction execution guarantees that any modifications to flags, registers, and memory for previous instructions are completed before the next instruction is fetched and executed.