SUB (array accumulators)

Subtract multi-vector from ZA array vector accumulators

Destructively subtract all elements of the two or four source vectors from the corresponding elements of the ZA single-vector groups.

The single-vector group within each half of or each quarter of the ZA array is selected by the sum of the vector select register and offset , modulo half or quarter the number of ZA array vectors.

The vector group symbol, VGx2 or VGx4, indicates that the ZA operand consists of two or four ZA single-vector groups respectively. The vector group symbol is preferred for disassembly, but optional in assembler source code.

This instruction is unpredicated.

ID_AA64SMFR0_EL1.I16I64 indicates whether the 64-bit integer variant is implemented.

It has encodings from 2 classes: Two ZA single-vectors and Four ZA single-vectors

Two ZA single-vectors
(FEAT_SME2)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); if sz == '1' && !IsFeatureImplemented(FEAT_SME_I16I64) then EndOfDecode(Decode_UNDEF); constant integer v = UInt('010':Rv); constant integer esize = 32 << UInt(sz); constant integer m = UInt(Zm:'0'); constant integer offset = UInt(off3); constant integer nreg = 2;

Four ZA single-vectors
(FEAT_SME2)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); if sz == '1' && !IsFeatureImplemented(FEAT_SME_I16I64) then EndOfDecode(Decode_UNDEF); constant integer v = UInt('010':Rv); constant integer esize = 32 << UInt(sz); constant integer m = UInt(Zm:'00'); constant integer offset = UInt(off3); constant integer nreg = 4;