ate2: function()

in src/pair.js [357:463]
85 lines of code
9 McCabe index (conditional complexity)

        ate2: function(P1, Q1, R1, S1) {
            var fa, fb, f, x, n, n3, K, lv, lv2,
                Qx, Qy, Sx, Sy, A, B, NP,NR,r, nb, bt,
                i;

            n = new ctx.BIG(0);
			n3 = new ctx.BIG(0);
            K = new ctx.ECP2();

            if (ctx.ECP.CURVE_PAIRING_TYPE == ctx.ECP.BN) {
                fa = new ctx.BIG(0);
                fa.rcopy(ctx.ROM_FIELD.Fra);
                fb = new ctx.BIG(0);
                fb.rcopy(ctx.ROM_FIELD.Frb);
                f = new ctx.FP2(fa, fb);

                if (ctx.ECP.SEXTIC_TWIST == ctx.ECP.M_TYPE) {
                    f.inverse();
                    f.norm();
                }
            } 

			var P=new ctx.ECP2(); P.copy(P1); P.affine();
			var Q=new ctx.ECP(); Q.copy(Q1); Q.affine();
			var R=new ctx.ECP2(); R.copy(R1); R.affine();
			var S=new ctx.ECP(); S.copy(S1); S.affine();


            Qx = new ctx.FP(Q.getx()); 
            Qy = new ctx.FP(Q.gety()); 

            Sx = new ctx.FP(S.getx()); 
            Sy = new ctx.FP(S.gety()); 

            A = new ctx.ECP2();
            B = new ctx.ECP2();
            r = new ctx.FP12(1);

            A.copy(P);
            B.copy(R);

			NP = new ctx.ECP2();
			NP.copy(P);
			NP.neg();
			NR = new ctx.ECP2();
			NR.copy(R);
			NR.neg();

            nb = PAIR.lbits(n3,n);

            for (i = nb - 2; i >= 1; i--) {
                r.sqr();
                lv = PAIR.line(A, A, Qx, Qy);
                lv2 = PAIR.line(B, B, Sx, Sy);
				lv.smul(lv2);
                r.ssmul(lv);

                bt=n3.bit(i)-n.bit(i);

                if (bt == 1) {
                    lv = PAIR.line(A, P, Qx, Qy);
                    lv2 = PAIR.line(B, R, Sx, Sy);
					lv.smul(lv2);
                    r.ssmul(lv);
                }
                if (bt == -1) {
                    lv = PAIR.line(A, NP, Qx, Qy);
                    lv2 = PAIR.line(B, NR, Sx, Sy);
					lv.smul(lv2);
                    r.ssmul(lv);
                }
            }

            if (ctx.ECP.SIGN_OF_X == ctx.ECP.NEGATIVEX) {
                r.conj();
            }


            // R-ate fixup required for BN curves 
            if (ctx.ECP.CURVE_PAIRING_TYPE == ctx.ECP.BN) {
                if (ctx.ECP.SIGN_OF_X == ctx.ECP.NEGATIVEX) {
                    A.neg();
                    B.neg();
                }
                K.copy(P);
                K.frob(f);

                lv = PAIR.line(A, K, Qx, Qy);
                K.frob(f);
                K.neg();
                lv2 = PAIR.line(A, K, Qx, Qy);
				lv.smul(lv2);
                r.ssmul(lv);

                K.copy(R);
                K.frob(f);

                lv = PAIR.line(B, K, Sx, Sy);
                K.frob(f);
                K.neg();
                lv2 = PAIR.line(B, K, Sx, Sy);
				lv.smul(lv2);
                r.ssmul(lv);
            }

            return r;
        },