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SIMD ISAReturn TypeNameArgumentsInstruction Group
Neonfloat64x2_tvrsqrtsq_f64(float64x2_t a, float64x2_t b)Vector arithmetic / Reciprocal / Reciprocal square-root estimate
Description
Floating-point Reciprocal Square Root Step. This instruction multiplies corresponding floating-point values in the vectors of the two source SIMD&FP registers, subtracts each of the products from 3.0, divides these results by 2.0, places the results into a vector, and writes the vector to the destination SIMD&FP register.
Results
Vd.2D result
This intrinsic compiles to the following instructions:

FRSQRTS Vd.2D,Vn.2D,Vm.2D

Argument Preparation
a register: Vn.2Db register: Vm.2D
Architectures
A64

Operation

CheckFPAdvSIMDEnabled64();
bits(datasize) operand1 = V[n];
bits(datasize) operand2 = V[m];

bits(esize) element1;
bits(esize) element2;
FPCRType fpcr    = FPCR[];
boolean merge    = elements == 1 && IsMerging(fpcr);
bits(128) result = if merge then V[n] else Zeros();

for e = 0 to elements-1
    element1 = Elem[operand1, e, esize];
    element2 = Elem[operand2, e, esize];
    Elem[result, e, esize] = FPRSqrtStepFused(element1, element2);

V[d] = result;