REC_INV_SQRT_SHIFT
return t + reciprocal_scale(interval, rec_inv_sqrt << REC_INV_SQRT_SHIFT);
vars->rec_inv_sqrt = ~0U >> REC_INV_SQRT_SHIFT;
u32 invsqrt = ((u32)vars->rec_inv_sqrt) << REC_INV_SQRT_SHIFT;
vars->rec_inv_sqrt = val >> REC_INV_SQRT_SHIFT;