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From: Richard Henderson <richard.henderson@linaro.org>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: ricky@rzhou.org, Gabriele Svelto <gsvelto@mozilla.com>
Subject: Re: [PATCH] target/i386: fix operand size for VCOMI/VUCOMI instructions
Date: Tue, 9 May 2023 16:00:17 +0100	[thread overview]
Message-ID: <83d9c36a-2e85-46b0-0b5d-7674a3cb584b@linaro.org> (raw)
In-Reply-To: <20230509142639.253947-1-pbonzini@redhat.com>

On 5/9/23 15:26, Paolo Bonzini wrote:
> Compared to other SSE instructions, VUCOMISx and VCOMISx are different:
> the single and double precision versions are distinguished through a
> prefix, however they use no-prefix and 0x66 for SS and SD respectively.
> Scalar values usually are associated with 0xF2 and 0xF3.
> 
> Because of these, they incorrectly perform a 128-bit memory load instead
> of a 32- or 64-bit load.  Fix this by writing a custom decoding function.
> 
> I tested that the reproducer is fixed and the test-avx output does not
> change.
> 
> Reported-by: Gabriele Svelto<gsvelto@mozilla.com>
> Resolves:https://gitlab.com/qemu-project/qemu/-/issues/1637
> Fixes: f8d19eec0d53 ("target/i386: reimplement 0x0f 0x28-0x2f, add AVX", 2022-10-18)
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> ---
>   target/i386/tcg/decode-new.c.inc | 15 +++++++++++++--
>   1 file changed, 13 insertions(+), 2 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~


  reply	other threads:[~2023-05-09 15:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-09 14:26 [PATCH] target/i386: fix operand size for VCOMI/VUCOMI instructions Paolo Bonzini
2023-05-09 15:00 ` Richard Henderson [this message]
2023-05-09 15:09 ` Peter Maydell

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