Method add

app/src/ThirdParty/fast_float.h:3990–3990

  FASTFLOAT_CONSTEXPR20 bool mul(limb y) noexcept { return small_mul(vec, y); }

  FASTFLOAT_CONSTEXPR20 bool add(limb y) noexcept { return small_add(vec, y); }

  // multiply as if by 2 raised to a power.
  FASTFLOAT_CONSTEXPR20 bool pow2(uint32_t exp) noexcept { return shl(exp); }