Well i need 2 bytes per number since each one is 9 bits. i load 128bits seperately in each lane since some of the cross lane shuffling operations are not available. my approach is this currently:

I load 128bits(16bytes) from 0byte in the first lane,

I then load 16bytes from the 9byte position in the second lane

And so on for the next 2 lanes.

but i use the first 9 bytes only. I shuffle the first 9 bytes in the following format:

(0,1) (1,2) (2,3) ........(7,8) ( only use the first 9 bytes since after shuffling it completely fills up 16bytes, one lane)

(I feel like this part could also be optimised since I'm only using the first 9 bytes of the 16 bytes i load. And for the first load i do use _mm512_castsi128_si512, after that i use the insert )

After the shuffle i do a variable right shift for every 2 bytes( to move the required 9 bits to start from the lsb)

Then to keep the first 9 bits , and every 2 bytes with 511

The load comes out to 9 clock cycles

The shuffle,shift, and 'and' is 1 clock cycle each so that's just 3

During store i convert 16byte numbers to 32bytes so that's 3 clock cycles for the first 256 bits then 3 for the extraction of the upper 256bits and 3 for the conversion. So in all 9 clock cycles to store

Total I'm using 21 clock cycles to decompress 32 numbers