How to get 0 to 9 bits at the beginning of 4 bytes

[alex.]

After receive 4 bytes from tcp in string, it need to get the first 0 to 9 bits out.

It is a hex value. May I know how to do so.

Any suggestion, thanks.

[X.]

Probably the simplest is to AND your 4 bytes number (U32) with x3F or xFFC00000 depending on what you call the "first" bits (least significant or most significant).