Why WinXP isn’t supported on 3rd Gen i5?

I have found that Windows XP is not supported on 3rd Gen i5 Processors. Why is it so? Almost all OS like Windows 7,8.1 ,8, Linux, Ubuntu are supported but why not Windows XP? What is the reason behind the incompatibility of Windows XP with 3rd Gen i5 Processors? What can be done for developing the support?
