ln2_256h
x##N = (x##N - y##N * ln2_256h) - y##N * ln2_256l; \
x0 = (x0 - y0 * ln2_256h) - y0 * ln2_256l;
x1 = (x1 - y1 * ln2_256h) - y1 * ln2_256l;
x2 = (x2 - y2 * ln2_256h) - y2 * ln2_256l;
x3 = (x3 - y3 * ln2_256h) - y3 * ln2_256l;
x4 = (x4 - y4 * ln2_256h) - y4 * ln2_256l;
x5 = (x5 - y5 * ln2_256h) - y5 * ln2_256l;