Packing 2 bits into a large data type(INT64)

[Darshvino]

Hi @lemire,

I was the one to ask you for the reference for packing 2 bits into a larger data type yesterday.

Basically, what is the difference between SIMDcomp and FastPFor? And for the 2 bits of packing and unpacking which library can be used among the two?

Thanks

[Darshvino]

Basically what I want to do is, I have 2-bit values in int64:
something like this: 000000.........0000011, 000000.........0000010, 000000.........0000001,....... these are INT64 values.

I want to pack 32 2-bit values in one int64 value.

Example:

A = 0000.........10(64 bit), B = 0000........11(64 bit), C = 0000........01, and so on, these are int64 values containing 2-bit values.

Z = 101101...........(int64 value, containing packed values of A, B, C, D, .............. )

If you could help me to find the reference in your libraries, that would be great!

Thanks in advance

[lemire]

The question is not in reference to the library.

[lemire]

You appear to have a programming question. That is better taken to sites like stackoverflow. Please do not create issues in software libraries for library maintainers to address.

If you open an issue with a library, it should bear on the library. Do not raise generic programming questions.