The EVEX prefix (enhanced vector extension) and corresponding coding scheme is an extension to the 32-bit x86 (IA-32) and 64-bit x86-64 (AMD64) instruction set architecture. EVEX is based on, but should not be confused with the MVEX prefix[1] used by the Knights Corner processor.
The EVEX scheme is a 4-byte extension to the VEX scheme which supports the AVX-512 instruction set and allows addressing new 512-bit ZMM registers and new 64-bit operand mask registers.
With Advanced Performance Extensions, the Extended EVEX prefix redefines the semantics of several payload bits.[2]
- ^ Intel® Xeon Phi™ Coprocessor Instruction Set Architecture Reference Manual (PDF). Sep 7, 2012. p. 42. 327364-001. Archived (PDF) from the original on Aug 4, 2021.
- ^ Intel® Advanced Performance Extensions (Intel® APX) Architecture Specification (PDF) (2 ed.). August 2023. p. 21. 355828-002US. Archived (PDF) from the original on Sep 10, 2023.