[__arm_]vshlq[_s16]

The immediate variant shifts each element of a vector register to the left by the immediate value. The register variants shift each element of a vector register by the value specified in a source register. The direction of the shift depends on the sign of the element from the second vector register. The vector variant shifts each element of the first vector by a value from the least significant byte of the corresponding element of the second vector and places the results in the destination vector.