function for bit rotation

anybody help me to explain following bit rotation function :

function[data,nBits]=bit_rotate(data,nBits)

dataBits=log2(double(intmax(class(data)))+1);

nBits=rem(nBits,dataBits);

if nBits==0

return

end

shiftedData=bitshift(data,nBits);

lostData=bitxor(data,bitshift(shiftedData,-nBits));

rotatedData=bitshift(lostData,nBits-sign(nBits)*dataBits);

data=shiftedData + rotatedData;

end

[KALYAN ACHARJYA]

Read here about rem, bitshift and bitxor or any specifc line?