CPUID

The CPUID instruction (identified by a CPUID opcode) is a processor supplementary instruction (its name derived from CPU IDentification) for the x86 architecture allowing software to discover details of the processor. It was introduced by Intel in 1993 when it introduced the Pentium and SL-enhanced 486 processors.CPUID.01.EDX.CLFSH = 1The nearest power-of-2 integer that is not smaller than this value is the number of unique initial APIC IDs reserved for addressing different logical processors in a physical package.CPUID.01.EDX.HTT = 1It can also be identified via the cpuid 0BH leaf ( CPUID.0Bh.EDX ).BNDLDX and BNDSTX Intel MPX instructions in 64-bit modeMSR The CPUID instruction (identified by a CPUID opcode) is a processor supplementary instruction (its name derived from CPU IDentification) for the x86 architecture allowing software to discover details of the processor. It was introduced by Intel in 1993 when it introduced the Pentium and SL-enhanced 486 processors. A program can use the CPUID to determine processor type and whether features such as MMX/SSE are implemented. Prior to the general availability of the CPUID instruction, programmers would write esoteric machine code which exploited minor differences in CPU behavior in order to determine the processor make and model.