On Wed, Oct 10, 2012 at 05:12:16PM +0200, Ronny Meeus wrote:

Do you have any clue (rough) on the amount of effort this change would cost?

David Daney's reply should give you more information for an estimate.

About the limited gain we can discuss: if you have a large application
that has been created assuming 32bit and it needs to be ported to a
64bit architecture, I think the effort can be huge and the risk for
forgetting things is high. It will be very hard to check whether the
system behaves well under all conditions.

A 64-bit port could start right away without the delay of waiting for
a usable N32-4GB.  Added benefit - with N64 you can grow beyond the 3GB.

Downside, due to larger pointers thus better cache locality 32-bit code
generally performs better.  And I agree that verification of N32-4GB
probably is easier than for a large application that wasn't written
with the intend of 64-bit support.

In my past as a contractor I've dealth with a few customers who were
trying to avoid going 64-bit at all cost.  They had to pay that cost ...

  Ralf