Messages in this thread | | | From | Yuhong Bao <> | Subject | RE: [X86] Fix up silly i1586 boot message. | Date | Tue, 27 Oct 2009 20:08:11 -0700 |
| |
<Pine.LNX.4.55.0805290102340.29522@cliff.in.clinika.pl> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0
> Intel started it first with picking up a ridiculous number for the family > ID for the P4 line. There is no technical justification for not keeping > these numbers consecutive.=20 Well=2C the problem was that Intel has assigned family 7 for the original I= tanium processor=2C back when Intel thought that would replace x86 (the cod= ename for the original Itanium was P7=2C and the codename for the original = P4 was P68). And then there was a bug in original NT 4 truncating family ID= s returned by CPUID to 3 bits. This was not the only bug in the original NT= 4's CPUID code=2C there was another bug relating to CX8 detection with non= -Intel/AMD/Cyrix processors forcing the other CPU vendors to provide an opt= ion to mask this bit=2C which caused trouble for MS itself later on when th= ey decide they would begin to require CX8 in XP=2C and it ignores CPUID if = max standard CPUID level is greater than 3=2C forcing Intel to again add a = workaround into their Prescott and later processors. Geoff Chappell wrote articles describing these problems in NT 4: http://geoffchappell.com/viewer.htm?doc=3Dstudies/windows/km/cpu/index.htm http://geoffchappell.com/viewer.htm?doc=3Dstudies/windows/km/cpu/cx8.htm
Yuhong Bao =20 _________________________________________________________________ Windows 7: It helps you do more. Explore Windows 7. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=3DPID24727::T:= WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen3:102009=
| |