From: Keir Fraser <keir.xen@gmail.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Don Slutz <dslutz@verizon.com>, xen-devel@lists.xen.org
Subject: Re: test_x86_emulator
Date: Wed, 16 Apr 2014 10:32:41 +0100 [thread overview]
Message-ID: <534E4E39.50105@gmail.com> (raw)
In-Reply-To: <534E5AE40200007800009550@nat28.tlf.novell.com>
Jan Beulich wrote:
> x86: fix instruction emulator test's xgetbv constraints
>
> The "A" constraint, while documented up to gcc4.5 as "The a and d
> registers, as a pair (for instructions that return half the result in
> one and half in the other)," never really behaved that (natural) way,
> but always meant (and is now also documented so) %eax_or_ %edx (%rax
> _or_ %rdx on x86-64) unless the operand was wide enough to require both
> (i.e. more than 32 bits on ix86 and more than 64 bits on x86-64).
>
> Interestingly something internal to the compiler changed between4.4
> and4.5 to actually expose the difference - up to gcc4.4 I was unable
> to construct a case where, when only the low half of the result is
> actually looked at, the result would be considered to be in %edx/%rdx
> (and %eax/%rax would be treated as unmodified by the instruction).
>
> Signed-off-by: Jan Beulich<jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
next prev parent reply other threads:[~2014-04-16 9:32 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-08 14:24 [PATCH v2 00/10] Prevent one cause of "MP-BIOS bug: 8254 timer"... message from linux Don Slutz
2014-04-08 14:24 ` [PATCH v2 01/10] hvm/hpet: Add manual unit test code Don Slutz
2014-04-09 16:08 ` Jan Beulich
2014-04-09 18:35 ` Don Slutz
2014-04-10 6:11 ` Jan Beulich
2014-04-11 2:53 ` Don Slutz
2014-04-11 7:45 ` Jan Beulich
2014-04-11 11:57 ` [PATCH optional " Don Slutz
2014-04-11 12:09 ` Jan Beulich
2014-04-11 12:48 ` Don Slutz
2014-04-11 15:14 ` Jan Beulich
2014-04-11 17:40 ` Don Slutz
2014-04-14 7:40 ` Jan Beulich
2014-04-14 17:29 ` test_x86_emulator (was Re: [PATCH optional v2 01/10] hvm/hpet: Add manual unit test code.) Don Slutz
2014-04-15 6:49 ` test_x86_emulator Jan Beulich
2014-04-15 14:24 ` test_x86_emulator Don Slutz
2014-04-16 8:26 ` test_x86_emulator Jan Beulich
2014-04-16 9:32 ` Keir Fraser [this message]
2014-04-16 15:21 ` test_x86_emulator Don Slutz
2014-04-08 14:24 ` [PATCH v2 02/10] hvm/hpet: Only call guest_time_hpet(h) one time per action Don Slutz
2014-04-14 14:31 ` Jan Beulich
2014-04-14 17:38 ` Don Slutz
2014-04-08 14:24 ` [PATCH v2 03/10] hvm/hpet: Only set comparator or period not both Don Slutz
2014-04-14 14:58 ` Jan Beulich
2014-04-14 22:53 ` Don Slutz
2014-04-15 6:59 ` Jan Beulich
2014-04-16 4:06 ` Don Slutz
2014-04-08 14:24 ` [PATCH v2 04/10] hvm/hpet: In hpet_save, correctly compute mc64 Don Slutz
2014-04-08 14:24 ` [PATCH v2 05/10] hvm/hpet: Init comparator64 like comparator Don Slutz
2014-04-08 14:24 ` [PATCH v2 06/10] hvm/hpet: comparator can only change when master clock is enabled Don Slutz
2014-04-14 15:07 ` Jan Beulich
2014-04-14 19:50 ` Don Slutz
2014-04-15 7:05 ` Jan Beulich
2014-04-15 15:53 ` Don Slutz
2014-04-15 16:14 ` Jan Beulich
2014-04-15 18:11 ` Don Slutz
2014-04-16 8:42 ` Jan Beulich
2014-04-08 14:24 ` [PATCH v2 07/10] hvm/hpet: Call hpet_get_comparator during hpet_save Don Slutz
2014-04-14 15:13 ` Jan Beulich
2014-04-15 0:21 ` Don Slutz
2014-04-15 7:06 ` Jan Beulich
2014-04-15 14:18 ` Don Slutz
2014-04-08 14:24 ` [PATCH v2 08/10] hvm/hpet: Prevent master clock equal to comparator while enabled Don Slutz
2014-04-08 14:24 ` [PATCH v2 09/10] hvm/hpet: Correctly limit period to a maximum Don Slutz
2014-04-08 14:24 ` [PATCH v2 10/10] hvm/hpet: handle 1st period special Don Slutz
2014-04-14 15:27 ` Jan Beulich
2014-04-15 0:21 ` Don Slutz
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