STEP_C2          1167 ext/gd/libgd/gd_topal.c       inc2 = inc2 * (2 * STEP_C2) + STEP_C2 * STEP_C2;
STEP_C2          1188 ext/gd/libgd/gd_topal.c 		  xx2 += 2 * STEP_C2 * STEP_C2;