SQRDMLSH (indexed)

Signed saturating rounding doubling multiply-subtract high from accumulator (indexed)

Multiply then double all signed elements within each 128-bit segment of the first source vector and the specified signed element of the corresponding second source vector segment, and destructively subtract the rounded high half of each result to the corresponding elements of the addend and destination vector. Each destination element is saturated to the 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 which 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, encoded in 1 to 3 bits depending on the size of the element.

It has encodings from 3 classes: 16-bit , 32-bit and 64-bit

16-bit

if !HaveSVE2() && !HaveSME() then UNDEFINED; constant integer esize = 16; integer index = UInt(i3h:i3l); integer n = UInt(Zn); integer m = UInt(Zm); integer da = UInt(Zda);

32-bit

if !HaveSVE2() && !HaveSME() then UNDEFINED; constant integer esize = 32; integer index = UInt(i2); integer n = UInt(Zn); integer m = UInt(Zm); integer da = UInt(Zda);

64-bit

if !HaveSVE2() && !HaveSME() then UNDEFINED; constant integer esize = 64; integer index = UInt(i1); integer n = UInt(Zn); integer m = UInt(Zm); integer da = UInt(Zda);