How to access hardware-accelerated CRC32C?

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Jens Alfke

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Sep 25, 2015, 3:31:59 PM9/25/15

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Current Intel CPUs have hardware instructions for performing the basic cycle of a CRC32C checksum. I’m porting a library that uses CRC32C and I’d like to use the fastest implementation possible. However, I haven’t found a public system API that provides any form of CRC32 (not even veclib) and the implementations I’ve found online are pure software (no assembly, just C.)

Is there a system API I overlooked? It’d be nice to call a built-in one instead of trying to do it myself, because of course I’d need to check what CPU type the code is running on, and then compare agains the exact set of Intel CPUs that support the opcode … yuck.

—Jens
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Jens Ayton

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Sep 28, 2015, 2:45:37 AM9/28/15

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On 25 Sep 2015, at 21:31, Jens Alfke <je...@mooseyard.com> wrote:
>
> …because of course I’d need to check what CPU type the code is running on, and then compare agains the exact set of Intel CPUs that support the opcode … yuck.

According to the Fine Manual (http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html Vol. 1 5-5), "Processor support of CRC32 is enumerated by CPUID.01:ECX[SSE4.2] = 1".