Vesta
English
Source code

MOVNTI

Store Doubleword Using Non-Temporal Hint

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
NP 0F C3 /rMOVNTI m32, r32MRValidValidMove doubleword from r32 to m32 using non-temporal hint.
NP REX.W + 0F C3 /rMOVNTI m64, r64MRValidNot encodableMove quadword from r64 to m64 using non-temporal hint.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

MR

  1. modrm.rm escrituraModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them
  2. modrm.reg lecturaModRM byte, reg field (bits 5-3)

Measured cost

Loading measurements from arch-data...

Description

Moves the doubleword integer in the source operand (second operand) to the destination operand (first operand) using a non-temporal hint to minimize cache pollution during the write to memory. The source operand is a general-purpose register. The destination operand is a 32-bit memory location.

The non-temporal hint is implemented by using a write combining (WC) memory type protocol when writing the data to memory. Using this protocol, the processor does not write the data into the cache hierarchy, nor does it fetch the corresponding cache line from memory into the cache hierarchy. The memory type of the region being written to can override the non-temporal hint, if the memory address specified for the non-temporal store is in an uncacheable (UC) or write protected (WP) memory region. For more information on non-temporal stores, see "Caching of Temporal vs. Non-Temporal Data" in Chapter 10 in the Intel(R) 64 and IA-32 Architectures Software Developer's Manual, Volume 1.

Because the WC protocol uses a weakly-ordered memory consistency model, a fencing operation implemented with the SFENCE or MFENCE instruction should be used in conjunction with MOVNTI instructions if multiple processors might use different memory types to read/write the destination memory locations.

In 64-bit mode, the instruction's default operation size is 32 bits. Use of the REX.R prefix permits access to additional registers (R8-R15). Use of the REX.W prefix promotes operation to 64 bits. See the summary chart at the beginning of this section for encoding data and limits.

Operation

DEST := SRC;

Intel C/C++ compiler intrinsics

MOVNTI void _mm_stream_si32 (int *p, int a) MOVNTI void _mm_stream_si64(__int64 *p, __int64 a);

SIMD Floating-Point Exceptions

None.

Exceptions

Protected mode
#GP(0)For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.
#SS(0)For an illegal address in the SS segment. #PF(fault-code) For a page fault.
#UDIf CPUID.01H:EDX.SSE2[26] = 0. If the LOCK prefix is used.
Real address mode
#GPIf any part of the operand lies outside the effective address space from 0 to FFFFH.
#UDIf CPUID.01H:EDX.SSE2[26] = 0. If the LOCK prefix is used.
Virtual-8086 mode
Same exceptions as in real address mode.
Compatibility mode
Same exceptions as in protected mode.
64-bit mode
#SS(0)If a memory address referencing the SS segment is in a non-canonical form.
#GP(0)If the memory address is in a non-canonical form. #PF(fault-code) For a page fault.
#UDIf CPUID.01H:EDX.SSE2[26] = 0. If the LOCK prefix is used.
#AC(0)If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.

Sources