Intel® C++ Compiler Classic Developer Guide and Reference

ID 767249
Date 7/13/2023
Public
Document Table of Contents

_mm_i32gather_epi32, _mm256_i32gather_epi32

Gathers 2/4 doubleword values from memory referenced by the given base address, dword indices, and scale. The corresponding Intel® AVX2 instruction is VPGATHERDD.

Syntax

extern __m128i _mm_i32gather_epi32(int const * base, __m128i vindex, const int scale);

extern __m256i _mm256_i32gather_epi32(int const * base, __m256i vindex, const int scale);

Arguments

base

the base address used to reference the loaded dword elements.

vindex

the vector of dword indices used to reference the loaded dword elements.

scale

The compilation time literal constant, which is used as the vector indices scale to address the loaded elements. Possible values are one of the following: 1, 2, 4, 8.

Description

The intrinsics load 2/4 doubleword values from memory using the base address, qword indices, and 32-bit scale.

Below is the pseudo-code for the intrinsics:

_mm_i32gather_epi32():

result[31:0] = mem[base+vindex[31:0]*scale];
result[63:32] = mem[base+vindex[63:32]*scale];
result[95:64] = mem[base+vindex[95:64]*scale];
result127:96] = mem[base+vindex[127:96]*scale];

_mm256_i32gather_epi32():

result[31:0] = mem[base+vindex[31:0]*scale];
result[63:32] = mem[base+vindex[63:32]*scale];
result[95:64] = mem[base+vindex[95:64]*scale];
result127:96] = mem[base+vindex[127:96]*scale];
result[159:128] = mem[base+vindex[159:128]*scale];
result[191:160] = mem[base+vindex[191:160]*scale];
result[223:192] = mem[base+vindex[223:192]*scale];
result[255:224] = mem[base+vindex[255:224]*scale];

Returns

A 128/256-bit vector with unconditionally gathered integer32 values.