vex prefix造句

• Instructions coded with the VEX prefix can have up to five operands.
• The VEX prefix " replaces " the most commonly used instruction prefix bytes and escape codes.
• All SSE5 instructions that were equivalent or similar to instructions in the AVX with the 3-byte VEX prefix.
• However, the VEX coding scheme has space for applying the VEX prefix to other instructions as well in future instruction sets.
• The VEX prefix's initial-byte values, C4h and C5h, are the same as the opcodes of the LDS and LES instructions.
• Various bit-fields in the VEX prefix's second byte are inverted to ensure that the byte is always of this form in 32-bit mode.
• The VEX prefix provides a compact representation of the REX prefix, as well as various other prefixes, to expand the addressing mode, register enumeration and operand size and width:
• The VEX prefix can also be used on the legacy SSE instructions giving them a three-operand form, and making them interact more efficiently with AVX instructions without the need for VZEROUPPER and ZEROALL.
• The "'VEX prefix "'( from " vector extensions " ) and "'VEX coding scheme "'are comprising an extension to the x86 and x86-64 instruction set architecture for microprocessors from Intel, AMD and others.
• The width of the SIMD register file is increased from 128 bits to 256 bits, and renamed from SSE instructions ( which previously operated on 128-bit XMM registers ) can be extended using the VEX prefix to operate on the lower 128 bits of the YMM registers.
• In many cases, the number of prefix bytes and escape bytes that are replaced is the same as the number of bytes in the VEX prefix, so that the total length of the VEX-encoded instruction is the same as the length of the legacy instruction code.