CPUID
↑ On Pentium Pro (GenuineIntel Family 6 Model 1) processors only, EDX bit 11 is invalid - the bit it set, but the SYSENTER and SYSEXIT instructions are not supported on the Pentium Pro.
↑ FCMOV and FCOMI instructions only available if onboard x87 FPU also present (indicated by EDX bit 0).
↑ ECX bit 16 is listed as "Reserved" in public Intel and AMD documentation and is not set in any known processor. However, some versions of the Windows Vista kernel are reported to be checking this bit - if it is set, Vista will recognize it as a "processor channels" feature.
↑ On non-Itanium x86 processors, support for the No-execute bit is indicated in CPUID.(EAX=8000_0001):EDX[bit 20] instead.