http://en.wikipedia.org/wiki/X86-64
The x86-64 specification was designed by Advanced Micro Devices (AMD), who
have since renamed it AMD64.[1] Intel has implemented it under the name
Intel 64 (formerly EM64T or IA-32e) in its own x86 processors.[2] VIA
Technologies has also included x86-64 instructions in their VIA Isaiah
architecture. The names x86-64 or x64 are often used as vendor-neutral terms
to collectively refer to x86-64 processors from any company.
