fix startup subroutine linking in VM

docs/source/todo.rst

@@ -3,9 +3,6 @@ TODO
 
 For next minor release
 ^^^^^^^^^^^^^^^^^^^^^^
-- fix IR/VM: animals.p8 example is borked, it jumps straight to a suggestion and then somehow doesn't print the animal name correctly in the first question, and exits after 1 animal instead of looping
-  this has happened after v8.7:  caused by c21913a6  ir: keep order of children in block  22-11-2022
-
 ...
 
 

examples/cx16/keyboardhandler.p8

@@ -2,6 +2,9 @@
 %zeropage basicsafe
 %option no_sysinit
 
+; The documentation for custom PS2 key handlers can be found here:
+; https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2002%20-%20Editor.md#custom-keyboard-scancode-handler
+
 main {
 
     sub start() {
@@ -69,6 +72,9 @@ main {
         ; Unfortunately this also means you cannot decide from that prog8 code
         ; if the keyboard press should be consumed/ignored or put into the keyboard queue
         ; (this is controlled by returning 0 or 1 in register A here)
+        ;
+        ; see:
+        ; https://github.com/X16Community/x16-docs/tree/X16%20Reference%20-%2002%20-%20Editor.md#custom-keyboard-scancode-handler
 
         %asm {{
             php

virtualmachine/src/prog8/vm/VmProgramLoader.kt

@@ -23,9 +23,11 @@ class VmProgramLoader {
         // make sure that if there is a "main.start" entrypoint, we jump to it
         irProgram.blocks.firstOrNull()?.let {
             if(it.children.any { sub -> sub is IRSubroutine && sub.label=="main.start" }) {
-                val chunk = IRCodeChunk(null, null)
+                val previous = programChunks.lastOrNull()
+                val chunk = IRCodeChunk(null, previous)
                 placeholders[Pair(chunk, 0)] = "main.start"
                 chunk += IRInstruction(Opcode.JUMP, labelSymbol = "main.start")
+                previous?.let { p -> p.next = chunk }
                 programChunks += chunk
             }
         }