SDOT (2-way, indexed)

Signed integer dot product by indexed element (two-way)

This instruction calculates the dot product of a pair of signed 8-bit or 16-bit integer values held in each 16-bit or 32-bit element of the first source vector multiplied by a pair of signed 8-bit or 16-bit integer values in an indexed 16-bit or 32-bit element of the second source vector, and then destructively adds the widened dot product to the corresponding 16-bit or 32-bit element of the destination vector.

The groups within the second source vector are specified using an immediate index that selects the same group position within each 128-bit vector segment. The index range is from 0 to one less than the number of groups per 128-bit segment.

This instruction is unpredicated.

It has encodings from 2 classes: 8-bit to 16-bit and 16-bit to 32-bit

8-bit to 16-bit
(FEAT_SVE2p3 || FEAT_SME2p3)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SVE2p3) && !IsFeatureImplemented(FEAT_SME2p3) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 16; let index : integer = UInt(i3h::i3l); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let da : integer = UInt(Zda);

16-bit to 32-bit
(FEAT_SME2 || FEAT_SVE2p1)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) && !IsFeatureImplemented(FEAT_SVE2p1) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 32; let index : integer = UInt(i2); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let da : integer = UInt(Zda);