libmath-int128-perl binary package in Ubuntu Focal amd64

 Math::Int128 adds support for 128 bit integers, signed and unsigned, to Perl.
 .
 The API is comparable to Math::Int64, just s/64/128/g ;-)
 .
 Besides that, as object allocation and destruction has been found to be a
 bottleneck, an alternative set of operations that use their first argument as
 the output (instead of the return value) is also provided.

Source package