Why does inverting the parameters to a CMPGT comparison function work as a CMPLT?

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I'm working with AVX2 in the process of optimizing a small mathematics library for a project, however, I've stumbled into minor inconsistencies.

AVX2 lacks the support for a CMPLT function for packed 32b i's, which is unfortunate. An alternative measure to create such an operation resides in the _mm256_cmpgt_epi32 function using a practice called "property transposition," apparently.

Reference:

_mm256_cmpgt_epi32(a,b)

Expectedly, the computation of a > b would be the desired input, however, to achieve our nonexistent _mm256_cmplt_epi32() function, we'd need to write out the inverse of our original input like so: _mm256_cmpgt_epi32(b,a).

My question being: Why does inerverting the input change the functions' operation to one which should have already been provided ( that being _mm256_cmplt_epi32 )?



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