_mm_mask_i64gather_pd, _mm256_mask_i64gather_pd

Gathers 2/4 packed double-precision floating point values from memory referenced by the given base address, qword indices and scale, and using the given double precision FP mask values. The corresponding Intel® AVX2 instruction is VGATHERQPD.

Syntax

extern __m128d _mm_mask_i64gather_pd(__m128d def_vals, double const * base, __m128i vindex __m128d vmask, const int scale);

extern __m256d _mm256_mask_i64gather_pd(__m256d def_vals, double const * base, __m128i vindex __m256d vmask, const int scale);

Arguments

def_vals

the vector of double-precision FP values copied to the destination when the corresponding element of the double-precision FP mask is '0'.

base

the base address used to reference the loaded FP elements.

vindex

the vector of qword indices used to reference the loaded FP elements.

vmask

the vector of FP elements used as a vector mask; only the most significant bit of each data element is used as a mask.

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 conditionally load 2/4 packed double-precision floating-point values from memory using qword indices according to mask values.

Below is the pseudo-code for the intrinsics:

_mm_mask_i64gather_pd():

result[63:0] = (vmask[63]==1) ? (mem[base+vindex[63:0]*scale]) : (def_vals[63:0]);
result[127:64] = (vmask[127]==1) ? (mem[base+vindex[127:64]*scale]) : (def_vals[127:64]);

_mm256_mask_i64gather_pd():

result[63:0] = (vmask[63]==1) ? (mem[base+vindex[63:0]*scale]) : (def_vals[63:0]);
result[127:64] = (vmask[127]==1) ? (mem[base+vindex[127:64]*scale]) : (def_vals[127:64]);
result[191:128] = (vmask[191]==1) ? (mem[base+vindex[191:128]*scale]) : (def_vals[191:128]);
result[255:192] = (vmask[255]==1) ? (mem[base+vindex[255:192]*scale]) : (def_vals[255:192]);

Returns

A 128/256-bit vector with conditionally gathered double-precision values.

Para obtener información más completa sobre las optimizaciones del compilador, consulte nuestro Aviso de optimización.