64 bit Intels?

[Mark Hahn]

>> Have the number of bits per machine instruction also increased to 64 bits?  

not exactly.  ia64 has "bundles" as its atomic instruction-stream format;
a 128b bundle contains three 41b instruction fields as well as a template
field. the legal combinations of instruction fields are fairly constrained,
which means that the compiler is somtimes (often?) forced to put nops
into bundles.

> instructions).  Are all pointers consistantly using 64 bits?  If so, there
> will be a proportional growth in the size of your executable.

how often are pointers encoded in your executables?  not often, I think.

> The larger architecture also impacts your data formats. If your data sets
> are in binary format, and depending on the language you are using, there
> may be incompatibilities as well as new demands on storage.

it's easy to say that ia64 is/was a pretty crazy thing to do,
but Intel isn't quite *that* far gone that they'd define wholly
new data formats.  modulo the usual endian considerations,
they're using familiar 2's complement integers and IEEE FP.

for PR-level slides:
http://developer.intel.com/design/itanium/idfisa/index.htm

for programmer-level intro:
http://developer.intel.com/design/itanium/downloads/24531703s.htm