I have two bytes (8 bits each) I need to combine these into one interger. And then split the top 12 bits into one integer and the bottom 4 bits into another integer.

i.e A = 0xFE
B = 0x03

First step combine two bytes: = 0xFE03
binary - 11111110 00000011

then split -------- ----++++ - = top 12 bits, + bottom 4 bits

then store seperatly

so one integer equals 0000111111100000
and the other equals 0000000000000011


Sorry it is hard to explain, please help.