Re: [PATCH] target/i386: fix incorrect decoding of EXTRQ_i

Richard Henderson <[email protected]>
Newsgroups gmane.comp.emulators.qemu
Message-ID <[email protected]>
On 6/25/26 08:56, Simon Scherer wrote:
> The decoding of the extrq instruction with an immediate operand (EXTRQ_i) is
> incorrect. Per the AMD manual the instruction encoding looks as follows:
> 
> EXTRQ xmm1, imm8, imm8   66 0F 78 /0 ib ib
> 
> The /0 indicates that the "Reg" field of the ModR/M byte must be equal
> to 0 and the XMM register operand is specified by the "R/M" field.
> However, qemu incorrectly uses the "Reg" field to extract the register operand.
> 
> This patch instead extracts the XMM register operand from the "R/M"
> field.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3611
> Signed-off-by: Simon Scherer <[email protected]>
> ---
>   target/i386/tcg/decode-new.c.inc | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Richard Henderson <[email protected]>


r~
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