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Copying low 16 bytes of YMM register to the high 16 bytes

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Robert Prins

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Nov 12, 2023, 4:02:38 PM11/12/23
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Or is there a way to immediately load a full YMM register with two copies of of
a 16 byte variable?

I've been looking at the various PSHUFxxx instructions, but they seem to stare
me in the face like Edgar Allan Poe's "Stolen letter"...

Thanks,

Robert
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Branimir Maksimovic

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Nov 12, 2023, 10:06:03 PM11/12/23
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On 2023-11-12, Robert Prins <rob...@nospicedham.prino.org> wrote:
> Or is there a way to immediately load a full YMM register with two copies of of
> a 16 byte variable?
>
> I've been looking at the various PSHUFxxx instructions, but they seem to stare
> me in the face like Edgar Allan Poe's "Stolen letter"...
>
> Thanks,
>
> Robert
VBROADCASTI128 is instuction you need.

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Robert Prins

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Nov 13, 2023, 5:21:42 AM11/13/23
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On 2023-11-13 02:59, Branimir Maksimovic wrote:
> On 2023-11-12, Robert Prins <rob...@nospicedham.prino.org> wrote:
>> Or is there a way to immediately load a full YMM register with two copies of
>> of a 16 byte variable?
>>
>> I've been looking at the various PSHUFxxx instructions, but they seem to
>> stare me in the face like Edgar Allan Poe's "Stolen letter"...

> VBROADCASTI128 is instruction you need.

Thanks! ...but given that my program must also run on an AMD Bulldozer CPU, I'm
SOL, I'll just have to double the data I'm loading. C'est la vie.
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