add Spy's Demise captive demo

res/attract-mode.txt

@@ -1,3 +1,34 @@
+# List of candidates for self-running 'captive' demos
+#
+# Not all games are good candidates. Some have no demo mode at all.
+# Others technically have one but it's visually uninteresting or too short.
+# Others are ruled out by technical constraints. Due to the architecture of
+# the launcher, all captive demos must run entirely in main memory (48K).
+# NO languard card, NO auxmem!
+#
+# We have enough disk space that we don't worry too much about it. (Wow.)
+# Generally we start with an uncompressed ProDOS port of the entire game
+# and whittle it down to just the files it needs for its demo mode, then
+# apply patches so that it
+#
+# - returns control after the natural end of the demo cycle
+# - returns control on any keypress
+# - returns control on any button press (note: some games don't support
+#   joystick buttons at all, and we don't add button support, but if you
+#   can start the game by pressing a button, we need to ensure that that
+#   returns control instead)
+# - disables all sound output
+#
+# 'Returning control' involves activating RAM bank 1 read access and
+# jumping to $D000 (labeled as |Reenter| in the source code). The launcher
+# puts this code at $0100 before executing a captive demo, so generally
+# you can just put 'JMP $0100' anywhere. If a particular game overwrites
+# this area of the stack page, you will need to find 6 bytes for the
+# 'LDA $C088 / JMP $D000' instructions yourself.
+#
+# Notes on completed and in-progress captive demos are in res/notes/
+#
+
 # TODO
 Agent USA
 Alien Ambush
@@ -5,7 +36,6 @@ Alien Downpour
 Alien Rain
 Apple Cider Spider
 Aquatron
-Arkanoid
 Bouncing Kamungas
 Buzzard Bait
 Canyon Climber
@@ -34,7 +64,6 @@ Pac-Man
 Pie-Man
 Plasmania [priority]
 Pooyan [priority]
-Prince of Persia
 Repton
 Ribbit
 Robotron 2084
@@ -69,5 +98,7 @@ Spare Change
 Wavy Navy
 
 # obvious candidates that we're skipping
+Arkanoid (requires 64K)
 Drol (attract mode is minimal)
 Mr. Do (attract mode requires 64K)
+Prince of Persia (requires 128K)

res/notes/spys-demise.txt

@@ -3,3 +3,4 @@ no support for joystick buttons
 
 $60D1: E0D0F0 -> 4C0001 to exit when user presses key during title page (context is 4C0A61AE00C010DFE0D0F020)
 $69B9: 68688D -> 4C0001 to exit when user presses key during demo (context is 49FF8527E636AD00C0100868688D10C0)
+$6D70: 4C4A60 -> 4C0001 to exit after demo cycle ends (context is A517C901D0034C4A60201662A529)