How can I add and subtract 128 bit integers in C or C++ if my compiler does not support them?

Question

I\'m writing a compressor for a long stream of 128 bit numbers. I would like to store the numbers as differences -- storing only the difference between the numbers rather th

Answer 1

TomsFastMath is a bit like GMP (mentioned above), but is public domain, and was designed from the ground up to be extremely fast (it even contains assembly code optimizations for x86, x86-64, ARM, SSE2, PPC32, and AVR32).