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From: Paolo Bonzini <pbonzini@redhat.com>
To: Rob Landley <rob@landley.net>,
	"Richard W.M. Jones" <rjones@redhat.com>,
	Thomas Huth <thuth@redhat.com>
Cc: qemu-devel@nongnu.org, "Marc Marí" <markmb@redhat.com>
Subject: Re: [Qemu-devel] Commit b2a575a1c652 broke i486 support.
Date: Wed, 31 May 2017 14:34:08 +0200	[thread overview]
Message-ID: <074f4da1-85de-ddd9-f426-ffb0ed563449@redhat.com> (raw)
In-Reply-To: <7e4d7d67-3312-2d2a-ab64-8c0f171d9118@landley.net>



On 30/05/2017 21:05, Rob Landley wrote:
> On 05/29/2017 05:14 AM, Richard W.M. Jones wrote:
>> I see in the disassembly use of cmovne (new in Pentium Pro) and
>> bswap (new in 486).
>> [http://cse.unl.edu/~goddard/Courses/CSCE351/IntelArchitecture/InstructionSetSummary.pdf]
>>
>> The cmovne instruction is generated by the compiler (GCC in my case),
>>
>> The following patch removes the cmovne instruction, so it should work
>> on 486 (although I didn't test it).  It's not possible to remove bswap
>> without surgery on the inline assembler.
> 
> Is there any way to make it just _not_ load the option rom for -cpu 486?
> It ran fine before that thing went in...

You were loading another option ROM.  Thomas's suggested -global
invocation will revert to that ROM until we fix it.

Paolo

      parent reply	other threads:[~2017-05-31 12:34 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-28  5:18 [Qemu-devel] Commit b2a575a1c652 broke i486 support Rob Landley
2017-05-29  9:22 ` Thomas Huth
2017-05-29 10:14   ` Richard W.M. Jones
2017-05-29 11:20     ` Thomas Huth
2017-05-30 19:05     ` Rob Landley
2017-05-31  8:58       ` Thomas Huth
2017-05-31  9:03       ` Richard W.M. Jones
2017-05-31 12:34       ` Paolo Bonzini [this message]

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