# _mm_mask_i64gather_ps, _mm256_mask_i64gather_ps

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

## Syntax

extern __m128 _mm_mask_i64gather_ps(__m128 def_vals, float const * base, __m128i vindex, __m128 vmask, const int scale);

extern __m128 _mm256_mask_i64gather_ps(float const * base, __m256i vindex, __m256i vmask, const int scale);

## Arguments

def_vals | the vector of single-precision FP values copied to the destination when the corresponding element of the single-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 single-precision floating-point values from memory using qword indices and updates the destination operand. The intrinsic `_mm_mask_i64gather_ps()` also sets the upper 64-bits of the result to '0'.

Below is the pseudo-code for the intrinsics:

`_mm_mask_i64gather_ps()`:

    result[31:0] = (vmask[31]==1) ? (mem[base+vindex[63:0]*scale]) : (def_vals[31:0]);
    result[63:32] = (vmask[63]==1) ? (mem[base+vindex[127:64]*scale]) : (def_vals[63:32]);
    result[127:64] = 0;

`_mm256_mask_i64gather_ps()`:

    result[31:0] = (vmask[31]==1) ? (mem[base+vindex[63:0]*scale]) : (def_vals[31:0]);
    result[63:32] = (vmask[63]==1) ? (mem[base+vindex[127:64]*scale]) : (def_vals[63:32]);
    result[95:64] = (vmask[95]==1) ? (mem[base+vindex[191:128]*scale]) : (def_vals[95:64]);
    result[127:96] = (vmask[127]==1) ? (mem[base+vindex[255:192]*scale]) : (def_vals[127:96]);

## Returns

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

Parent topic: Intrinsics for GATHER Operations