Have you seen this page?

Posted May 27, 2011 14:03 UTC (Fri) by marcH (subscriber, #57642)
In reply to: Have you seen this page? by dgm
Parent article: What Every C Programmer Should Know About Undefined Behavior #3/3

It's a matter of both: 1. Choose the architecture, 2. Apply the maths specific to this architecture.

GMP or else can help for the latter (of course not for the former).