Sascha Retzki <lantis@iqranet.info> writes:

> I heared that IA64 ( Intel Itanium ) are not a ia32-extension like the amd64,
> but have an own instruction set. Can somebody enlight me? :)

That's correct. IA64 is a novel architecture developed by Intel, with
some influence from HP and the HP-PA architecture. It doesn't really
look like conventional x86 code at all. In fact, it doesn't generally
resemble any other ISA, except in bits and pieces.

The architecture includes an IA32 mode for backwards-compatibility,
but it's much more like having a second chip bolted on, or running an
emulator in firmware. In contrast, the AMD 64-bit ISA is a
straightforward extention of the 32-bit x86 ISA.

        - Nathan