SQDMULLB (indexed)

Signed saturating doubling multiply by indexed element (bottom)

This instruction multiplies the even-numbered signed elements within each 128-bit segment of the first source vector by the specified element in the corresponding second source vector segment, and then doubles and places the results in overlapping double-width elements of the destination vector register. Each result element is saturated to the double-width N-bit element's signed integer range -2^(N-1) to (2^(N-1))-1.

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

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

32-bit
(FEAT_SVE2 || FEAT_SME)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) 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 d : integer = UInt(Zd); let sel : integer = 0;

64-bit
(FEAT_SVE2 || FEAT_SME)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 32; let index : integer = UInt(i2h::i2l); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let d : integer = UInt(Zd); let sel : integer = 0;