Date: Fri, 30 Jul 2010 21:39:28 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r210665 - head/sys/amd64/amd64 Message-ID: <201007302139.o6ULdSj0082218@svn.freebsd.org>
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Author: delphij Date: Fri Jul 30 21:39:28 2010 New Revision: 210665 URL: http://svn.freebsd.org/changeset/base/210665 Log: In rdmsr_safe, use zero extend (by doing a 32-bit movl over eax to itself) instead of a sign extend. Discussed with: stas MFC after: 1 month Modified: head/sys/amd64/amd64/support.S Modified: head/sys/amd64/amd64/support.S ============================================================================== --- head/sys/amd64/amd64/support.S Fri Jul 30 21:28:25 2010 (r210664) +++ head/sys/amd64/amd64/support.S Fri Jul 30 21:39:28 2010 (r210665) @@ -729,7 +729,7 @@ ENTRY(rdmsr_safe) rdmsr /* Read MSR pointed by %ecx. Returns hi byte in edx, lo in %eax */ salq $32,%rdx /* sign-shift %rdx left */ - cltq /* sign-extend %eax -> %rax */ + movl %eax,%eax /* zero-extend %eax -> %rax */ orq %rdx,%rax movq %rax,(%rsi) xorq %rax,%rax
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