BFMAX (multiple vectors)

Multi-vector BFloat16 floating-point maximum

Determine the maximum of BFloat16 elements of the two or four second source vectors and the corresponding BFloat16 elements of the two or four first source vectors and destructively place the results in the corresponding elements of the two or four first source vectors.

When FPCR.AH is 0, the behavior is as follows:

• Negative zero compares less than positive zero.
• When FPCR.DN is 0, if either element is a NaN, the result is a quiet NaN.
• When FPCR.DN is 1, if either element is a NaN, the result is Default NaN.

When FPCR.AH is 1, the behavior is as follows:

• If both elements are zeros, regardless of the sign of either zero, the result is the second element.
• If either element is a NaN, regardless of the value of FPCR.DN, the result is the second element.

This instruction follows SME2 non-widening BFloat16 numerical behaviors corresponding to instructions that place their results in two or four SVE Z vectors.

This instruction is unpredicated.

ID_AA64SMFR0_EL1.B16B16 indicates whether this instruction is implemented.

It has encodings from 2 classes: Two registers and Four registers

Two registers
(FEAT_SVE_B16B16)

if !IsFeatureImplemented(FEAT_SME2) || !IsFeatureImplemented(FEAT_SVE_B16B16) then UNDEFINED; constant integer dn = UInt(Zdn:'0'); constant integer m = UInt(Zm:'0'); constant integer nreg = 2;

Four registers
(FEAT_SVE_B16B16)

if !IsFeatureImplemented(FEAT_SME2) || !IsFeatureImplemented(FEAT_SVE_B16B16) then UNDEFINED; constant integer dn = UInt(Zdn:'00'); constant integer m = UInt(Zm:'00'); constant integer nreg = 4;