# _mm256_slli_si256

Logical shift of byte elements to left according to specified number. The corresponding Intel® AVX2 instruction is `VPSLLDQ`.

## Syntax

extern __m256i _mm256_slli_si256(__m256i s1, const int count);

## Arguments

s1 | integer source vector used for the operation
count | 8-bit immediate used for the operation

## Description

Performs a logical shift of 8-bit [byte] elements within a 128-bit lane of the source vector s1 to the left by the number of bytes specified in count. The empty low-order bytes are cleared (set to all '0'). If the value specified by count is greater than 15, the destination vector is set to all 0s. The count argument is an 8-bit immediate.

## Returns

Result of the left-shift operation.

Parent topic: Intrinsics for Logical Shift Operations