fix timing & logs/*.png generation

demo/timing.c

@@ -290,7 +290,7 @@ int main(void)
          }
          printf("Exponentiating\t%4d-bit => %9" PRIu64 "/sec, %9" PRIu64 " cycles\n",
                 mp_count_bits(&a), CLK_PER_SEC / tt, tt);
-         FPRINTF((n < 4) ? logd : (n < 9) ? logc : (n < 16) ? logb : log,
+         FPRINTF((n < 3) ? logd : (n < 9) ? logc : (n < 16) ? logb : log,
                  "%6d %9" PRIu64 "\n", mp_count_bits(&a), tt);
       }
    }

logs/Makefile

@@ -0,0 +1,2 @@
+all:
+	gnuplot graphs.dem

logs/graphs.dem

@@ -1,5 +1,4 @@
 set terminal png
-set size 1.75
 set ylabel "Cycles per Operation"
 set xlabel "Operand size (bits)"