Function get_error

system/lib/llvm-libc/src/math/generic/cbrt.cpp:62–65

//   h(x) = x^3 * a^2 - 1,
#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE
double get_error(const DoubleDouble &x_3, const DoubleDouble &a_sq) {
  return fputil::multiply_add(x_3.hi, a_sq.hi, -1.0) +
         fputil::multiply_add(x_3.lo, a_sq.hi, x_3.hi * a_sq.lo);
}
#else
double get_error(const DoubleDouble &x_3, const DoubleDouble &a_sq) {
  DoubleDouble x_3_a_sq = fputil::quick_mult(a_sq, x_3);