SQRDCMLAH (vectors)

Saturating rounding doubling complex integer multiply-add high with rotate

Multiply without saturation the duplicated real components for rotations 0 and 180, or imaginary components for rotations 90 and 270, of the integral numbers in the first source vector by the corresponding complex number in the second source vector rotated by 0, 90, 180 or 270 degrees in the direction from the positive real axis towards the positive imaginary axis, when considered in polar representation.

Then double and add the products to the corresponding components of the complex numbers in the addend vector. Destructively place the most significant rounded half of the results in the corresponding elements of the addend vector. Each result element is saturated to the N-bit element's signed integer range -2^(N-1) to (2^(N-1) )-1. This instruction is unpredicated.

These transformations permit the creation of a variety of multiply-add and multiply-subtract operations on complex numbers by combining two of these instructions with the same vector operands but with rotations that are 90 degrees apart.

Each complex number is represented in a vector register as an even/odd pair of elements with the real part in the even-numbered element and the imaginary part in the odd-numbered element.

if !HaveSVE2() && !HaveSME() then UNDEFINED; integer esize = 8 << UInt(size); integer n = UInt(Zn); integer m = UInt(Zm); integer da = UInt(Zda); integer sel_a = UInt(rot<0>); integer sel_b = UInt(NOT(rot<0>)); boolean sub_r = (rot<0> != rot<1>); boolean sub_i = (rot<1> == '1');