On 23.07.2024 15:47, Alejandro Vallejo wrote: > On Mon Jul 22, 2024 at 11:18 AM BST, Andrew Cooper wrote: >> + if ( (eax >> 16) != 0x8000 || eax < 0x80000000U ) >> + blexit(L"In 64bit mode, but no extended CPUID leaves?!?"); > > I'm not sure about the condition even for the old code. If eax had 0x90000000 > (because new convention appeared 10y in the future), then there would be > extended leaves but we would be needlessly bailing out. Why not simply check > that eax < 0x80000001 in here?
eax = 0x90000000 is in leaf group 0x9000, not in the extended leaf group (0x8000). The splitting into groups may not be written down very well, but you can see the pattern in e.g. groups 0x8086 and 0xc000 also being used (by non-Intel non-AMD hardware), without those really being extended leaves in the sense that 0x8000xxxx are. Jan
