Advanced Micro Devices Inc (AMD)

[Dan3]

Re: who's going to port the 1000s of Windows drivers to 64-bit so that people can run Windows 64 on their desktop?

For Opteron/Athlon-64, with millions of new users expected in the next few quarters, everyone - especially since it's so easy to port to this wonderfully compatible architecture.

For the few thousand buyers of Itanium and its weird new platform, very few. You've done a fine job of pointing out why Itanium can't seem to get anywhere.

As mentioned previously, 32-bit apps run under the 64-bit version of Windows without translation or emulation. The only “help” such applications receive is that 32-bit system service calls are “thunked” (extended) to their 64-bit equivalents. This is entirely transparent to the application.

And The Drivers?

For most drivers, moving to the AMD-64 is trivial. Here at OSR we’ve already ported several drivers to support AMD-64. All that’s required will be a careful read-through of the code to ensure 64-bit compliance (discussed below) and re-compiling using the 64-bit compiler provided as part of the DDK.

An interesting fact to note is that the AMD-64 uses the “longlong pointer” architecture model. This means that while pointers become 64-bit values (with a data type of ULONGLONG), the ULONG data type stays 32-bits. This significantly eases the process of moving your driver to the AMD-64. Note that this is different from some Unix systems, where when moving from a 32-bit to a 64-bit system the LONG data type becomes 64-bits long.
http://www.osronline.com/article.cfm?id=243