SMOPA (4-way)

Signed integer sum of outer products, accumulating

The 8-bit integer variant works with a 32-bit element ZA tile.

The 16-bit integer variant works with a 64-bit element ZA tile.

This instruction multiplies the sub-matrix in the first source vector by the sub-matrix in the second source vector. In case of the 8-bit integer variant, the first source holds SVL_S×4 sub-matrix of signed 8-bit integer values, and the second source holds 4×SVL_S sub-matrix of signed 8-bit integer values. In case of the 16-bit integer variant, the first source holds SVL_D×4 sub-matrix of signed 16-bit integer values, and the second source holds 4×SVL_D sub-matrix of signed 16-bit integer values.

Each source vector is independently predicated by a corresponding governing predicate. When an 8-bit source element in case of 8-bit integer variant or a 16-bit source element in case of 16-bit integer variant is Inactive, it is treated as having the value 0.

The resulting SVL_S×SVL_S widened 32-bit integer or SVL_D×SVL_D widened 64-bit integer sum of outer products is then destructively added to the 32-bit integer or 64-bit integer destination tile, respectively for 8-bit integer and 16-bit integer instruction variants. This is equivalent to performing a 4-way dot product and accumulate to each of the destination tile elements.

In case of the 8-bit integer variant, each 32-bit container of the first source vector holds 4 consecutive column elements of each row of a SVL_S×4 sub-matrix, and each 32-bit container of the second source vector holds 4 consecutive row elements of each column of a 4×SVL_S sub-matrix. In case of the 16-bit integer variant, each 64-bit container of the first source vector holds 4 consecutive column elements of each row of a SVL_D×4 sub-matrix, and each 64-bit container of the second source vector holds 4 consecutive row elements of each column of a 4×SVL_D sub-matrix.

ID_AA64SMFR0_EL1.I16I64 indicates whether the 16-bit integer variant is implemented.

It has encodings from 2 classes: 32-bit and 64-bit

32-bit
(FEAT_SME)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 32; let a : integer = UInt(Pn); let b : integer = UInt(Pm); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let da : integer = UInt(ZAda); let op1_unsigned : boolean = FALSE; let op2_unsigned : boolean = FALSE;

64-bit
(FEAT_SME_I16I64)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME_I16I64) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 64; let a : integer = UInt(Pn); let b : integer = UInt(Pm); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let da : integer = UInt(ZAda); let op1_unsigned : boolean = FALSE; let op2_unsigned : boolean = FALSE;