Intel: x86, 32-bit on-die application support dropped for IA-64 Montecito

Hillsboro (OR) - This afternoon, an Intel spokesperson confirmed to TG Daily that the Montecito platform, which will premiere the company's next-generation 64-bit Itanium architecture, will dispense with executing all 32-bit instruction set applications on-die, prompting customers to opt instead for software-based emulation which Intel promises will be faster anyway.

The disposal of the on-die feature was discovered last week by CNET reporter Joris Evers, who noticed the omission of any mention of x86 platform emulation in an addendum manual for the Montecito platform released by Intel last week, entitled "Dual-Core Update to the Intel Itanium 2 Reference Manual." The update manual refers to the fact that first-generation IA-32 processing support had been moved from the hardware level, to emulation software called "IA-32 Execution Layer." "IA-32 EL is OS-based and is only available after an OS has booted," it states, which is the manual's way of saying it's a program on disk, not microcode on a chip.

What was unclear was whether this meant for certain that x86 emulation was being moved to IA-32 LA as well, or perhaps to some other unmentioned service. But in a statement to us this afternoon, Intel spokesperson Scott McLaughlin stated, "x86 software will run on Montecito using the IA32-EL emulation software rather than via an on-die solution."

At one time, support for 32-bit software was considered critical to IA-64's consideration as a full-featured platform. But the reasons for this change in direction, stated McLaughlin, are threefold: "First, IA32-EL is good code," he said, "and outperforms the hardware solution by [greater than a factor of three], and as the processor performance scales, so will the application performance.

"The second point is related," McLaughlin continued. "Application performance scales well through the emulation software, which means the customers get benefits without us having to re-spin or redesign transistors to deliver more performance. This is good for them, us, [as well as] system manufacturers who need to revalidate after every silicon spin. Finally, this lets us use the transistors that were focused on x86 software for other features in the processor."

Later, McLaughlin added that all of his 32-bit "legacy apps" run fine on the Itanium-2 64-bit platform, "which is all I care about, really."

With Intel's more consumer-related projects having stolen the spotlight, not much had been stated about Intel's plans for Montecito and Itanium 2 since last September's demonstration at the IDF conference.