Further evidence that Microsoft intends to support AMD's Sledgehammer chip comes from the company's own upcoming operating system revision, Whistler, aka Windows XP.

Specifically, the clue is to be found in Whistler's SDK (Software Development Kit) and its DDK (Driver Development Kit), which reference the upcoming 64-bit processor in a compiler directive. Here's an excerpt provided by a Register reader:

#elif defined (_AMD64_)
// These function [sic] are defined in amd64.h for the AMD64 platform.

We haven't explored the SDK, so we can't yet confirm the presence of a header file, amd64.h, and the compiler variable _AMD64_ , but if the are there, they certainly suggest that the Whistler SDK provides, in the form of a placeholder at the very least, information to allow software developers to build Windows apps that directly support AMD's x86-64 technology. And there's not much point doing that if the OS isn't planned to run on the chip too.

All this goes a little way to beef up comments, reported earlier today, that Microsoft is, at least internally, talking about Sledgehammer support. Externally, it has only offered generic 'we evaluate all new technologies' answers when asked about support for the Hammer family. ®

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