Full Basic version; the library source code and precompiled QuickLibraries for
QuickBasic 4.5, PDS 7.1 and Visual Basic for Dos 1.0 are packed with the largeint
demo modules. Includes a library version for the new, 32-bit Linux/Windοws FreeBasic compiler 0.90.1:

LargeInt.zip, 08-19-2013 333Kb

Supplement: modulo-polynomial arithmetic for PDS, VBdos and FreeBasic,
originally intended as a demonstration of the multiple homomorphic image method
(header file link).
New additions: factorization of polynomials over Z[X], computing cyclotomic polynomials,
Reed-Solomon error correction and the Elgamal cryptosystem in finite fields GF(p^n):

PolMods.zip, 01-11-2012 163Kb

Some sample VBwin projects (Fibonacci, pi, cryptography) to illustrate the use of my
largeint library with Visual Basic. Also includes a tiny rational/real big number class for Excel.
The last addition is a RPN big integer calculator,
doubling as library shell.
These projects utilize the power of the FreeBasic compiled BigNum VB.dll

BigNumVB.zip, 05-27-2010 116Kb

This version is an adaptation for the 32/64-bit Linux/Windοws XBasic 6.2.3 language.
The packet includes the library source code with a precompiled BigNum XB.dll
and 33 selected modules together with sample inputfiles:

BigNumXB.zip, 06-06-2011 152Kb

Comparative note:

My library is purposely designed for supplying large integer arithmetic in standard Basic's. If you need to work on big real numbers, then Yuji Kida's fine 2600-digit UBasic package is the tool of choice. This free interpreter allows fast calculations with complex numbers and polynomials as well.As an illustration of the differences between the standard (e.g. QBasic) and UBasic syntax, I have implemented two versions of Ferguson and Bailey's PSLQ algorithm for finding integer relations among a set of real numbers. PSLQ is already a modern classic, therefore a must to include with my number theory tools:

PSLQ.zip, 02-23-2008 14Kb

As a bonus, there's this random collection of Basic math modules from the vaults
(combinatorics, continued fraction arithmetic, cryptography, matrices, Riemann zeta fun),
including single-precision models of a few largeint modules:

Single-p.zip, 12-01-2009 115Kb

Encoded list of prime numbers below 10,000,000 primflgs.bin
used by library function Nxtprm.