diff --git a/tasking.68k b/tasking.68k
index 2a9e3d6..56b8700 100644
--- a/tasking.68k
+++ b/tasking.68k
@@ -110,6 +110,11 @@ tnp_as_copy:
   rts
 
 tasking_um_switch_shim:
+  move.l (a7)+, a0 ; Get the target PC into a0
+  ; Push a dummy format/vector word
+  move.w #0, -(a7)
+  ; Push the PC
+  move.l a0, -(a7)
   move.w sr, d0 ; Push the SR with the supervisor bit cleared to make a "fake" exception frame
   andi.w #(~$2000), d0
   move.w d0, -(a7)