How to simulate 8bytes double???

From: Auronc (auronc_at_sinamail.com)
Date: 09/08/04 

Date: 8 Sep 2004 05:56:55 -0700

Because my special compiler,I am looking for some class, which support
8 bytes double. I found my machine only supports 4 bytes for (double).
I need the operation: + - * / sin() cos() atan2()..etc.
Are there any kind soul to help me? Thanks a lot.