Reciprocal of square root (double precision) (Reciprocal of the Square Root of a Floating-point Value (Double))
This instruction obtains the arithmetic positive square root of the double-precision floating-point format contents of the register pair specified by general-purpose register reg1, then approximates the reciprocal of this result and stores the result in the register pair specified by general-purpose register reg2.
The result differs from the result obtained when using a combination of the sqrtf and divf instructions.