38 	h[4] = f[4] + g[4];  in fadd()
55 	h[4] = (f[4] + ((prime51[4] * 2))) - g[4];  in fsub()
112 	fe51 x1, x2, z2, x3, z3;  in curve25519_fe51()  local
123 	z2[0] = z2[1] = z2[2] = z2[3] = z2[4] = 0;  in curve25519_fe51()
128 	x3[4] = x1[4];  in curve25519_fe51()
130 	x2[0] = z3[0] = 1;  in curve25519_fe51()
131 	x2[1] = z3[1] = 0;  in curve25519_fe51()
132 	x2[2] = z3[2] = 0;  in curve25519_fe51()
133 	x2[3] = z3[3] = 0;  in curve25519_fe51()
134 	x2[4] = z3[4] = 0;  in curve25519_fe51()
143 		x25519_cswap(x2, x3, swap);  in curve25519_fe51()
147 		fsub(b, x2, z2);		// B = x_2 - z_2  in curve25519_fe51()
148 		fadd(a, x2, z2);		// A = x_2 + z_2  in curve25519_fe51()
158 		fmul(x2, aa, bb);		// x2 = AA * BB  in curve25519_fe51()
171 	fmul(x2, x2, z2);  in curve25519_fe51()
172 	fe51_tobytes(out, x2);  in curve25519_fe51()