size; i++ { xLimbs[i], c = bits.Add(xLimbs[i], yLimbs[i], c) } return } // sub computes x -= y. It returns the borrow of the subtraction. // // Both operands must have the same announced length. // //go:norace func (x *Nat) sub(y *Nat) (c uint) { // Eliminate bounds checks in the loop. size := len(x.limbs) xLimbs := x.limbs[:size] yLimbs := y.limbs[:size] for i := 0; i < size; i++ { xLimbs[i], c = bits.Sub(xLimbs[i], yLimbs[i], c) } return } // ShiftRightVarTime sets x = x >> n. // // The announced length...