zsbc
zsbc is a bc-language calculator working with libgmp
...When running with libbc numbers lib, it works with decimal numbers (and it manages the "scale" variable = number of decimals)
When running with libgmp numbers lib, it works with integers only.
zsbc works on Windows and Linux.
zsbc was created just for fun and to work on cryptographic topics.
It can handle an expression like
2^10^100%97 (it'll replace it with powmod(2, 10^100, 97) on-the-fly).
It can also implicitly calculate invmod's as in:
1/4%7 that (if variable autoinvmod is set) will return 2.