A fine scoop by the San Jose Mercury apparently confirms the existence of Intel's 64bit Plan B, codenamed Yamhill.
According the Merc, Yamhill adds 64bit instructions to the existing x86 architecture, and may appear in the Prescott chips, "with an option to turn the features on or off." The emphasis is on 'may', as according to the former Yamhill engineer, no decision has been taken to proceed with Plan B.
It's not clear whether this is a new core, or simply new instructions onto the P7 core.
But it makes Itanic a harder sell then it already is: and Compaq and HP, who have pledged to end of life their own 64bit architectures in favour of IA-64, may well be wondering if they pulled the trigger too soon.
Itanium faces performance comparisons not just from the RISC rivals - with Sun and IBM investing heavily in their 64bit processors - but from Intel's own x86 line. This is often overlooked - but one of the consequences of the size and complexity of IA-64 is that it's the last to benefit from process improvements - McKinley will debut at 0.18 micron, when P4 is tooled to 0.13.
With IA-32 getting SMT, Intel's own x86 line would continue to provide stiff competition for the 64bit big brother.
And of course AMD will bring the Hammer - 64bit, backward-compatible x86 chip, to market.,
Although it's reasonable to assume that Yamhill features would make it harder for Intel to justify ongoing investment in IA-64, much of the hard work has been done in the ISV community. We'd be surprised if a parallel skunkworks to create a more economic, and thus more marketable Itanic, isn't already underway. For example, an Itanium without the complexity of the 32bit compatibility.
Sun (with MAJC), Transmeta (with Crusoe) and PACT (with XPP) all use explicity parallel VLIW architectures. Even if Intel decided that IA-64 wasn't ready for prime time, it has built up plenty of expertise in EPOC processor and compiler design and, would be loathe to throw this out, too. ®
In the absence of official word on Yamhill, we instead provide you this opportunity to look at the Yamhill Juvenile Offenders Detention Facility.