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AVX

avx-type-6 exception class

VEX-encoded instructions without a legacy SSE form, such as VBROADCASTSS, VINSERTF128, VPERM2I128 and VMASKMOVPS, which Intel's manual calls Exceptions Type 6.

Class
avx-type-6 in Intel XED
Applies to
VEX encodings only, including those of SHA512 and SM4.
Instructions
25 mnemonics, 79 forms
Data
Intel XED v2026.08.23

Exception conditions

When an instruction of the class raises each exception, and in which processor modes. Protected mode includes compatibility mode. How to read the table.
ExceptionRealVirtual-8086Protected64-bitCondition
#UDAlways: real and virtual-8086 mode have no VEX prefix.
#UDThe operating system has not enabled the AVX state: CR4.OSXSAVE is 0, or XCR0 bits 1 and 2 (SSE and AVX state) are not both 1.
#UDThe instruction has a LOCK prefix (F0).
#UDA REX, F2, F3 or 66 prefix comes before the VEX prefix.
#UDThe processor lacks the instruction’s extension: its CPUID feature flag is 0.
#NMCR0.TS (task switched, bit 3) is 1.
#SS(0)A memory operand addressed through SS lies outside the stack segment.
#SS(0)A memory operand addressed through SS has a non-canonical address.
#GP(0)A memory operand in the CS, DS, ES, FS or GS segment has an effective address that the segment does not allow, such as one beyond its limit.
#GP(0)A memory operand has a non-canonical address.
#PF(fault-code)Accessing a memory operand causes a page fault.
#AC(0)Code at privilege level 3 makes a misaligned 2-, 4- or 8-byte memory access while alignment checking is on.

Notes

The manual adds reasons for #UD to single instructions of the class:

  • VEX.W = 1: VEXTRACTF128, VBROADCASTSS, VBROADCASTSD, VBROADCASTF128, VINSERTF128, VMASKMOVPS, VMASKMOVPD, VBROADCASTI128, VPBROADCASTB, VPBROADCASTW, VPBROADCASTD, VEXTRACTI128 and VINSERTI128 (Table 2-16), and VPERM2F128 and VPERM2I128 (their pages).
  • VEX.L = 0: VEXTRACTF128, VPERM2F128, VBROADCASTSD, VBROADCASTF128 and VINSERTF128, which exist only as 256-bit forms (Table 2-17).

VMASKMOVPS and VMASKMOVPD never raise #AC, whatever their mask.

XED also puts VPERMILPD and VPERMILPS here. The manual’s pages refer their VEX forms to Type 4 instead, which has no #AC, and add #UD for VEX.W = 1.

  • avx-type-4: VEX-encoded integer, logical, shuffle and cryptographic instructions without floating-point exceptions, such as VPADDD, VPSHUFB and VAESENC, which Intel's manual calls Exceptions Type 4.
  • AVX512-E6: EVEX-encoded broadcasts and down-converting stores, such as VBROADCASTSS and VPMOVDB, with memory fault suppression, which Intel's manual calls Exceptions Type E6.
  • AVX512-E6NF: EVEX-encoded extracts and inserts of 128- and 256-bit lanes, such as VEXTRACTF32X4 and VINSERTI64X4, without fault suppression, which Intel's manual calls Exceptions Type E6NF.

Instructions

Intel XED puts forms of 25 mnemonics in this class, listed here by extension. Where a mnemonic also has forms of other classes, its link leads to its first form of this one.

AVX

AVX2

SHA512

SM4

Sources

  1. Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 2 (325383-093, September 2026): Section 2.5.6, Table 2-23; Section 2.5, Tables 2-14 to 2-17; Chapter 5, VMASKMOV, VPERM2F128, VPERM2I128, VPERMILPD and VPERMILPS.
  2. Intel XED v2026.08.23 (commit 0bcb6237345c): the exception class of each instruction form.

The list of instructions is derived from Intel XED, Copyright Intel Corporation, licensed under the Apache License 2.0; x86-64.net converted and reformatted it. The text is our own.