[PATCH] Exploiting dual mode operation, implementation.

[Leehod Baruch]

> Would you not want to merge se4 and use2 _before_ you place the
> remaining necessary sign-extends?
My question is general. 
I didn't mean to specify the phases of the algorithm or anything like that.
I just wanted to show that optimizing a web with a mixture of more then one pair
of modes is difficult. 
And thats why I would like to handle only webs that has only one pair of 
modes.

Leehod.