# Function: hwb4
# This file has been taken from RevLib (www.revlib.org). 
.i 4
.o 4
.ilb a b c d
.ob a b c d
0000 0000
0001 1000
0010 0001
0011 1100
0100 0010
0101 0101
0110 1001
0111 1110
1000 0100
1001 0110
1010 1010
1011 0111
1100 0011
1101 1011
1110 1101
1111 1111
.e