Hi,

Attached patch prevents duplication of quite similar code in fdc.c, and 
so, removes 300 lines and 8KB of code.
It first extracts implementation of FDC commands to separate methods, 
and then uses a table to know which method to execute instead of a big 
switch.

This patch takes cares of Blue Swirl's comments, and replaces linear 
search by a direct table lookup.

Hervé