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[Bug target/77756] __get_cpuid() returns wrong values for level 7 (extended features)
- From: "hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 29 Sep 2016 14:56:27 +0000
- Subject: [Bug target/77756] __get_cpuid() returns wrong values for level 7 (extended features)
- Auto-submitted: auto-generated
- References: <bug-77756-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77756
--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
Level 7 returns the maximum input value in EAX with ECX == 0.
Level 9 and 10 don't use ECX as input.
Level 11 takes ECX[7:0] as input level number.
Level 13 takes many values in ECX as input.
....
There is no fixed rule of ECX input for level >= 7.