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. - Wikipedia
Como podemos ver quem seguiu o rastro dessa vez foi a Intel.
A implementação do superset de instruções x86-64 foi implementado pela Intel com o nome EM64T ou IA-32e.
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