Xcode 2.2 has been release, and mentioned in the release notes was this little nugget:
Visual Studio compatible inline assembly: In order to provide migration
support for applications moving from other Intel platforms, we have begun to
provide VS inline assembly support. This work is not complete at this point butsupports many usages. Please file problem reports for missing functionality.
With this support, these game developers will find it much easier to bring such code over the MacOS.
This would have to be pure code, not something that calls out to any platform-specific APIs.
Maybe a physics engine or something. Then again, if you can dual-boot (or even better, switch-boot) to your game-playing OS (formerly known as Windows), why bother? Hm..