VZEROALL

simd_reg_file[][] is a two dimensional array representing the SIMD register file containing all the overlapping xmm, ymm, and zmm
registers present in that implementation. The major dimension is the register number: 0 for xmm0, ymm0, and zmm0; 1 for xmm1,
ymm1, and zmm1; etc. The minor dimension size is the width of the implemented SIMD state measured in bits. On a machine
supporting Intel AVX-512, the width is 512.

VZEROALL (VEX.256 encoded version)
IF (64-bit mode)

    limit :=15
ELSE

    limit := 7
FOR i in 0 .. limit:

    simd_reg_file[i][MAXVL-1:0] := 0

VZEROALL:    _mm256_zeroall();