Add code skeleton for the binary-tree-api:s unittest

wip-hugo/macros/16aritmatic.s

@@ -80,6 +80,7 @@
 
 ;;Larger then operation, uses the A register
 ;;IF a < b then: jump to label
+; C =0 if jump to LABEL
 .macro Lag_16 a_low, a_hi, b_low, b_hi, label ; [low, hi] = [low, hi]*2
         LDA a_hi
         CMP b_hi

wip-hugo/routines/line/line_down_inv.s

@@ -65,8 +65,8 @@ increment_y_pos_end:
         ;;If D <  %00000010 00000000:  case_2
         ;;else case 1.
         Lag_16 >D, <D, #$00, #$02, case_2
-case_1:
-        Sub_16 >D, <D, >V, <V; D = D - V
+case_1:; C = 1 because LAG
+        Sub_16 >D, <D, >V, <V, !; D = D - V
 increment_pixel_x:
         LDA byte_to_paint
         LSR byte_to_paint