This intrinsic inserts a VFP VSQRT instruction into the instruction stream generated by the compiler. It enables you to obtain the square root of a double‑precision floating‑point value from within your C or C++ code.
Note
The __sqrt intrinsic is an analogue of the standard C library function sqrt. It differs from the standard library function in that a call to __sqrt is guaranteed to be compiled into a single, inline, machine instruction on an ARM architecture‑based processor equipped with a VFP coprocessor.
double __sqrt(double val)
Where:
valis a double‑precision floating‑point value.
The __sqrt intrinsic returns the square root of val as a double.
The compiler does not recognize the __sqrt intrinsic when compiling for a target that is not equipped with a VFP coprocessor. The compiler generates either a warning or an error in this case.