Windows XP 32bit license can be used in 64bit

[Earth]

Hello,
everything is summarized in the title:
is it that you can use license provided for instance with a Windows XP 32-bit OEM for use with a 64bits OEM XP CD?
I know that Vista it is used in this case (and legal), I do not know if it's the same with XP.

Say that there are 2 questions:
Is this possible? (depending on the service pack?)
Is this legal? (if we use it only on a machine, a course)
If someone has the answer, I'm interested

[JAMES_911]

xp not theoretically since architectures are very different

[newtech]

The keys for XP 64 bit aren't compatible with XP 32bit and vice versa.

[EINSTEIN_007]

See suggestions given in similar type of thread:

Licensing Windows XP 32-bit and 64 bit