for now I can't provide you circuits because I have some things to do with my BGU, but I wanted to share this document I found:
https://upcommons.upc.edu/bitstream/han ... tAdder.pdf
witch shows a very convenient list of design steps to make an Add/Substract module, on pages 13 to 15
as logic circuit handles 32 bits wirestack, it wouldn't be too difficult to make.