No, x87/MMX and SSE XMM were not aliased. They were two separate register files.
(You may be confusing it with XMM vs YMM vs ZMM, i.e. SSE vs AVX vs AVX512.)
No, x87/MMX and SSE XMM were not aliased. They were two separate register files.
(You may be confusing it with XMM vs YMM vs ZMM, i.e. SSE vs AVX vs AVX512.)
It’s more likely they’re confusing it with 3DNow! (AMD’s own media extension focused on floating point math). That was strictly aliased and therefore an either/or situation on chips that had both.