diff --git a/mandel.s b/mandel.s
index 9840325..3419466 100644
--- a/mandel.s
+++ b/mandel.s
@@ -1549,11 +1549,11 @@ minus:
     dec zoom
     jmp done
 up:
-    sub32 oy, oy, temp
+    add32 oy, oy, temp
     jsr display_coords
     jmp done
 down:
-    add32 oy, oy, temp
+    sub32 oy, oy, temp
     jsr display_coords
     jmp done
 left:
@@ -1854,6 +1854,7 @@ not_skipped_mask:
     zoom_factor cx, sx, aspect_x
     add32 cx, cx, ox
     zoom_factor cy, sy, aspect_y
+    neg32 cy
     add32 cy, cy, oy
     jsr mandelbrot
     jsr pset