Begin using static in the demo game.

HISTORY.md

@@ -9,6 +9,7 @@ History of SixtyPical
     as `ld a, [ptr] + y` and `st a, [ptr] + y`.
 *   Implements the "union rule for trashes" when analyzing `if` blocks.
 *   Even if we `goto` another routine, we can't trash an output.
+*   `static` storage locations local to routines can now be defined within routines.
 *   Fixed bug where `trash` was not marking the location as being virtually altered.
 
 0.11

README.md

@@ -59,14 +59,6 @@ This should be tracked in the abstract interpretation.
 Range-checking buffers might be too difficult.  Range checking tables will be easier.
 If a value is ANDed with 15, its range must be 0-15, etc.
 
-### Routine-local static memory locations
-
-These would not need to appear in the inputs/outputs/trashes sets of the routines
-that call this routine.
-
-These might be forced to specify an initial value so that they can always be
-assumed to be meaningful.
-
 ### Re-order routines and optimize tail-calls to fallthroughs
 
 Not because it saves 3 bytes, but because it's a neat trick.  Doing it optimally

eg/proto-game.60p

@@ -37,7 +37,7 @@ typedef routine
   outputs button_down, dispatch_game_state,
           actor_pos, actor_delta, actor_logic,
           screen, screen1, screen2, screen3, screen4, colormap1, colormap2, colormap3, colormap4
-  trashes a, x, y, c, z, n, v, pos, new_pos, delta, ptr, save_x, compare_target, dispatch_logic
+  trashes a, x, y, c, z, n, v, pos, new_pos, delta, ptr, compare_target, dispatch_logic
     game_state_routine
 
 //
@@ -93,7 +93,6 @@ vector logic_routine dispatch_logic
 byte button_down : 0  // effectively static-local to check_button
 byte table[32] press_fire_msg: "PRESS`FIRE`TO`PLAY"
 
-byte save_x
 word compare_target
 
 //
@@ -410,6 +409,7 @@ define game_state_title_screen game_state_routine
 }
 
 define game_state_play game_state_routine
+static byte save_x : 0
 {
     ld x, 0
     repeat {