mist: redo directions (make them bitmask instead of ordinal)

this might break subtle things :(

mist/draw_pointer.s

@@ -18,15 +18,15 @@ draw_pointer:
 	cmp	#$ff
 	beq	finger_not_special	; if $ff not special
 
-	lda	(LOCATION_STRUCT_L),Y
-	cmp	#$4
-	beq	was_any
+;	lda	(LOCATION_STRUCT_L),Y
+;	cmp	#DIRECTION_ANY
+;	beq	was_any
 
 	lda	DIRECTION
 	and	#$f
 
-	cmp	(LOCATION_STRUCT_L),Y
-	bne	finger_not_special	; only special if facing right way
+	and	(LOCATION_STRUCT_L),Y
+	beq	finger_not_special	; only special if facing right way
 
 was_any:
 
@@ -147,9 +147,15 @@ check_cursor_right:
 	beq	finger_right
 	bne	finger_uturn_right
 
+log2_table:
+	;     0 1 2 3 4 5 6 7 8
+	.byte 0,0,1,1,2,2,2,2,3
+
 lookup_direction:
 	lda	DIRECTION
 	and	#$f
+	tay
+	lda	log2_table,Y
 	asl
 	asl
 	asl

mist/keyboard.s

@@ -154,6 +154,8 @@ no_split:
 
 done_split:
 	and	#$f			; mask off special flags
+	tay
+	lda	log2_table,Y
 	asl
 	clc
 	adc	#LOCATION_NORTH_BG
@@ -204,6 +206,8 @@ go_forward:
 
 	lda	DIRECTION
 	and	#$f
+	tay
+	lda	log2_table,Y
 	clc
 	adc	#LOCATION_NORTH_EXIT
 	tay
@@ -218,6 +222,8 @@ go_forward:
 
 	lda	DIRECTION
 	and	#$f
+	tay
+	lda	log2_table,Y
 	clc
 	adc	#LOCATION_NORTH_EXIT_DIR
 	tay

mist/zp.inc

@@ -37,11 +37,11 @@ CURSOR_Y= $63
 XPOS	= $64
 YPOS	= $65
 DIRECTION = $66
-	DIRECTION_N = $0
-	DIRECTION_S = $1
-	DIRECTION_E = $2
-	DIRECTION_W = $3
-	DIRECTION_ANY=$4
+	DIRECTION_N = $1
+	DIRECTION_S = $2
+	DIRECTION_E = $4
+	DIRECTION_W = $8
+	DIRECTION_ANY=$f
 	DIRECTION_ONLY_POINT = $40	; do not change pointer to grab
 	DIRECTION_SPLIT = $80		; split text/graphics
 LOCATION = $67