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.
The EVEXprefix (enhanced vector extension) and corresponding coding scheme is an extension to the 32-bit x86 (IA-32) and 64-bit x86-64 (AMD64) instruction...
Evex may refer to: Esterified estrogens, by brand name EVEXprefix This disambiguation page lists articles associated with the title Evex. If an internal...
with the EVEXprefix, but none of the instructions in those maps are VEX-encodable. The VEX2 prefix is a 2-byte variant of the VEX3 prefix, that differs...
instructions are encoded with the VEX or EVEXprefixes – on the form VEX.66.0F38 xy /r or EVEX.66.0F38 xy /r. The VEX.W/EVEX.W bit selects floating-point format...
2-byte REX2 prefix, while new instructions and extended operands for existing AVX/AVX2/AVX-512 instructions are encoded with extended EVEXprefix which has...
Advanced Performance Extensions, Foundation (adds REX2 and extended EVEXprefix encodings to support 32 GPRs, as well as some new instructions) 21 22...
floating-point arithmetic instructions that all follow a given pattern where: EVEX.W is used to specify floating-point format (0=FP32, 1=FP64) The bottom opcode...
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