_mm256_zeroupper

Zeroes the upper bits of the YMM registers. The corresponding Intel® AVX instruction is VZEROUPPER.

Syntax

extern void _mm256_zeroupper(void);

Arguments

None

Description

Zeroes the upper 128 bits of all YMM registers. The lower 128 bits that correspond to the XMM registers are left unmodified.

This intrinsic is useful to clear the upper bits of the YMM registers when transitioning between Intel® AVX and legacy SSE instructions. There is no transition penalty if an application clears the upper bits of all YMM registers (sets to ‘0’) via VZEROUPPER, the corresponding instruction for this intrinsic, before transitioning between Intel® AVX instructions and legacy SSE instructions.

Returns

Result of the operation.