I think you are basically there, but your table doesn't make much sense. ABCD represents a two's complement value. It IS a two's complement value. Your leftmost column is the bit pattern for -ABCD, which iisn't at issue here. This is the table I was trying to get you to come up with:
V|A|B|C|D||l0|eq0
0|0|0|0|0||0|1
1|0|0|0|1||0|0
2|0|0|1|0||0|0
3|0|0|1|1||0|0
4|0|1|0|0||0|0
5|0|1|0|1||0|0
6|0|1|1|0||0|0
7|0|1|1|1||0|0
-8|1|0|0|0||1|0
-7|1|0|0|1||1|0
-6|1|0|1|0||1|0
-5|1|0|1|1||1|0
-4|1|1|0|0||1|0
-3|1|1|0|1||1|0
-2|1|1|1|0||1|0
-1|1|1|1|1||1|0
0|0|0|0|0||0|1
1|0|0|0|1||0|0
2|0|0|1|0||0|0
3|0|0|1|1||0|0
4|0|1|0|0||0|0
5|0|1|0|1||0|0
6|0|1|1|0||0|0
7|0|1|1|1||0|0
-8|1|0|0|0||1|0
-7|1|0|0|1||1|0
-6|1|0|1|0||1|0
-5|1|0|1|1||1|0
-4|1|1|0|0||1|0
-3|1|1|0|1||1|0
-2|1|1|1|0||1|0
-1|1|1|1|1||1|0