Intel® C++ Compiler Classic Developer Guide and Reference

ID 767249
Date 12/16/2022
Public

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<span class='option'>_mm256_castpd128_pd256</span>

Typecasts 128-bit double-precision floating point values to 256-bit double-precision floating point values. No corresponding Intel® AVX instruction.

Syntax

extern __m256d _mm256_castpd128_pd256(__m128d a);

Arguments

a

128-bit float64 vector

Description

Performs a typecast operation from 128-bit double-precision floating point values to 256-bit double-precision floating point values.

The lower 128-bits of the 256-bit resulting vector contains the source vector values; the upper 128-bits of the resulting vector are undefined. This intrinsic does not introduce extra moves to the generated code.

Returns

A vector with 256-bit double-precision floating point values. The upper bits of the resulting vector are undefined.