1. XMM - Noun
2. XMM - Proper noun
XMM (plural XMMs)
(computing, dated) Initialism of Extended Memory Manager.
XMM
X-ray Multi-Mirror Mission
However, the new XMM register-file allowed SSE SIMD-operations to be freely mixed with either MMX or x87 FPU ops. Source: Internet
SSE2 adds two major features: double-precision (64-bit) floating point for all SSE operations, and MMX integer operations on 128-bit XMM registers. Source: Internet
SSE2 enables the programmer to perform SIMD math on any data type (from 8-bit integer to 64-bit float) entirely with the XMM vector-register file, without the need to use the legacy MMX or FPU registers. Source: Internet
SSE floating point instructions operate on a new independent register set (the XMM registers), and it adds a few integer instructions that work on MMX registers. Source: Internet