table.Select(p, sel) t := NewP256Point() for index >= 4 { index -= 5 p.Double(p) p.Double(p) p.Double(p) p.Double(p) p.Double(p) if index >= 0 { sel, sign = boothW5(s.Rsh(index) & 0b111111) } else { // Booth encoding considers a virtual zero bit at index -1, // so we shift left the least significant limb. wvalue := (s[0] << 1) & 0b111111 sel, sign = boothW5(wvalue) } table.Select(t, sel) t.Negate(sign) p.Add(p, t) } return p, nil } // Negate sets p to -p, if cond == 1, and to p if cond == 0. func (p *P256Point)...