public override ECFieldElement MultiplyPlusProduct(ECFieldElement b, ECFieldElement x, ECFieldElement y) { ulong[] ax = this.x, bx = ((SecT113FieldElement)b).x; ulong[] xx = ((SecT113FieldElement)x).x, yx = ((SecT113FieldElement)y).x; ulong[] tt = Nat128.CreateExt64(); SecT113Field.MultiplyAddToExt(ax, bx, tt); SecT113Field.MultiplyAddToExt(xx, yx, tt); ulong[] z = Nat128.Create64(); SecT113Field.Reduce(tt, z); return(new SecT113FieldElement(z)); }