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Hi Ruben,
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<div>They should be refined eventually, perhaps by adding an override accepting a part number following similar patterns in other places of the API. A reason why we have not prioritized this so far is: </div>
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<div>1) AFAICT there is currently no commonly available hardware that goes beyond a cache line size in vector size. Thereby reducing the urgency. I would be interested in knowing if my assumption is incorrect!</div>
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<div>2) There are related implementation issues when shuffling bytes, since the underlying shuffle implementation of bytes stores the indices in a byte[] array. This is more disruptive to address than the first one.</div>
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<div>Paul.<br id="lineBreakAtBeginningOfMessage">
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<div>On Jan 30, 2026, at 3:05 AM, Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com> wrote:</div>
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Hi all,</div>
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The question is related to Vector API compatibility with various vector lengths.</div>
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Some of the interfaces appear to be limiting support to 512-bit vectors, for example:</div>
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- VectorMask.toLong throws an exception for vectors with more than 64 lanes;</div>
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- VectorMask.fromLong replicates the sign bit into lane 64 and beyond.</div>
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As far as I understand from the documentation, the wider vectors are meant to be supported though not necessarily optimized for initially:</div>
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"Although the API has been designed to ensure ARM SVE instructions can be supported (vector sizes between 128 and 2048 bits)"</div>
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As the Java programs using the interfaces might not be compatible with an architecturally valid hardware platform, is there a possibility to refine the interfaces to ensure they scale to wider vectors?</div>
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Kind regards,</div>
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Ruben</div>
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