Change a variable to the opposite?

[Hylan]

Doh! Since you posted the truth table, you are correct that I did not RTFM. Before my original post I tried to but didn't know where to look. Now I do and since most of the code uses binary I used:
BCD_In = BCD_In ^ %11111111

Thank you for the pointers and help!

[falingtrea]

Is BCD value 9 the only value that needs translation? Could you actually need a BCD to grey code translation?

[ardhuru]

If your variable is always going to be 4 bits, the complement would be got by variable(comp) = 15-variable.

Regards,

Anand