XMM registers

The 128-bit XMM registers are part of the SSE extension (where SSE is short for Streaming SIMD Extension, and SIMD, in turn, stands for single instruction multiple data). There are eight XMM registers available in non -64-bit modes and 16 XMM registers in long mode, which allow simultaneous operations on:

• 16 bytes
• eight words
• four double words
• two quad words
• four floats
• two doubles

We will pay much more attention to these registers and the technology behind them in Chapter 5, Parallel Data Processing.