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Unsigned Reciprocal Square Root Estimate. This instruction reads each vector element from the source SIMD&FP register, calculates an approximate inverse square root for each value, places the result into a vector, and writes the vector to the destination SIMD&FP register. All the values in this instruction are unsigned integer values.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.



URSQRTE <Vd>.<T>, <Vn>.<T>

integer d = UInt(Rd);
integer n = UInt(Rn);

if sz == '1' then UNDEFINED;
integer esize = 32;
integer datasize = if Q == '1' then 128 else 64;
integer elements = datasize DIV esize;

Assembler Symbols


Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T> Is an arrangement specifier, encoded in sz:Q:
sz Q <T>
0 0 2S
0 1 4S

Is the name of the SIMD&FP source register, encoded in the "Rn" field.


bits(datasize) operand = V[n];
bits(datasize) result;
bits(32) element;

for e = 0 to elements-1
    element = Elem[operand, e, 32];
    Elem[result, e, 32] = UnsignedRSqrtEstimate(element);

V[d] = result;