*** ARC port for review ***

[cupertinomiranda]

Hello everyone,

Here is a long due refresh of ARC port patches.

The reason for taking so long was that I did a big refreshement to the
code due to the adition of the soon to release ARCv3 (64 bit) architecture.
In order to avoid further big changes in the original patches we decided to
delay the submittion and include all the changes done to support ARCv3.

Special thanks and apologies for Richard Henderson that has (long time ago)
given his feedback which unfortunately took us a while to address and improve.

Requests addressed:
 - Long list of fixes/improvements by Richard.
 - Generalization of the code to support both 32 and 64 bit targets.

Pending to be addressed:
 - Refactor of the decoder code which currently depends on string
   matching of the mnemonic.

In order to simplify the review process, we have separated the patches 
for ARCv3 from the previous emailed ARCv2 ones. Being the patches from
1 to 16 for ARCv2 and 17 to 27 for ARCv3.

Best regards,
Cupertino Miranda