# _mm256_castsi256_si128

Typecasts 256-bit integer values to 128-bit integer values. No corresponding Intel® AVX instruction.

## Syntax

extern __m128i _mm256_castsi256_si128(__m256i a);

## Arguments

a | 256-bit integer source vector

## Description

Performs a typecast operation from 256-bit integer values to 128-bit integer values.

The lower 128-bits of the source vector are passed unchanged to the result. This intrinsic does not introduce extra moves to the generated code.

## Returns

A vector with 128-bit integer values.

Parent topic: Support Intrinsics for Vector Typecasting Operations