lundi 23 février 2015

Optimal uint8_t bitmap into a 8 x 32bit SIMD "bool" vector

As part of a compression algorithm, I am looking for the optimal way to achieve the following:


I have a simple bitmap in a uint8_t. For example 01010011


What I want is a _m256i of the form: { 0, maxint, 0, maxint, 0, 0, maxint, maxint)


One way to achieve this is by shuffling a vector of 8 x maxint into a vector of zeros. But that first requires me to expand my uint8_t to the right shuffle bitmap.


I am wondering if there is a better way?


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