$ c1 =（$ c1＆0x03）<< 4是什么意思？

Question

Specifically, what does the ($c1 & 0x03) << 4 do?

Is 0x03 hex notation?

Answer 1

It does mean first operation do logically AND with HEX value 0x03(that is 3 in HEX or (0011) in Binary).and then left Shift 4 places.example

let u have $c = 34. then first it performs $c & 3 which is (100010 BITWISE AND 000011) which Gives you (000010) and then It shifts 4 digit on left position and restore new value in $c ie (100000) or 32 in decimal.

Hope it is Helpful.

Thanks

Answer 2

这将占用$c1值的低两位，并将其向左移动4位。

Answer 3

Yes 0x is hex. That is doing a bitwise AND of $c1 and the hex 03 value, then left shifting the result 4 places (powers of 2).