NES: rm $FF writes; improve Zapper in menu

Write to $00FF was used for a persistent debug breakpoint.
It does something in another environment.  Remove writes that
I'd forgotten to remove before.  Use $4444 instead henceforth.

Also the Zapper is more responsive in menus if the menu code
actually does nothing after finishing writing the page.

nes/src/help.s

@@ -492,6 +492,8 @@ pagenum_template_done:
   jmp have_line_buffer
 
 not_pagenum_line:
+  cmp #22        ; to improve Zapper responsiveness
+  bcs page_done  ; do nothing if the page is finished
 
   ; 0: End of page
   ; 1: End of page if not multicart

nes/src/helppages.txt

@@ -61,8 +61,8 @@ the A and Select Buttons.
 Start: Show relevant help
 B: Close activity
 
-CRT users can navigate menus
-with a Zapper in port 2.
+CRT users can navigate
+menus with a Zapper in port 2.
 Shoot item: Choose
 Shoot bottom: Change page
 Shoot top/offscreen: Back

nes/src/scrolltest.s

@@ -149,7 +149,7 @@ loop:
   notDecSpeed:
 
   dir_speed_change_done:
-  
+
   lda new_keys+0
   and #KEY_B
   bne done
@@ -269,7 +269,7 @@ nomove:
   sta PPUDATA
   inx
   bne :-
-  
+
   ldx #4
   jsr ppu_clear_oam
   stx OAM+0
@@ -301,7 +301,6 @@ nomove:
   bcc :+
     ldy #splittable_pal-splittable_ntsc
   :
-  sty $FF
 splitloop:
   ldx splittable_ntsc,y
   iny

nes/src/stills.s

@@ -433,7 +433,6 @@ restart:
 loop:
   lda need_reload
   beq not_reloading
-    sty $FF
     lda #0
     sta need_reload
     lda #120
@@ -462,7 +461,7 @@ loop:
     ldx #40
     jsr vwfPuts
 
-    ; Prepare for blitting    
+    ; Prepare for blitting
     lda #%0111
     jsr rf_color_lineImgBuf
     lda #$0F
@@ -501,7 +500,7 @@ loop:
     lda #$80
     sta vram_copydsthi
   :
-    
+
   ; And turn the display on
   ldx #0
   stx PPUSCROLL
@@ -700,7 +699,7 @@ pluge_shark_palettes:
   .byte $0F,$10,$02,$1C
   .byte $0F,$00,$0F,$0C
   .byte $10,$20,$32,$3C
-  
+
 .segment "CODE"
 .proc do_pluge
 palettechoice = test_state+0
@@ -910,7 +909,7 @@ sprite_x = $03
     cmp #160
     bcc sprboxloop
 
-  ; And hide the rest of sprites      
+  ; And hide the rest of sprites
   jsr ppu_clear_oam
 
 loop:
@@ -1052,7 +1051,7 @@ tvSystemFPS:  .byte 60, 50, 50
   sta vram_copydstlo
   lda #$00
   sta vram_copydsthi
-  rts 
+  rts
 .endproc
 
 .proc do_full_stripes
@@ -1108,7 +1107,7 @@ restart:
   tax
   lda bleed_types,x
   jsr rf_load_layout
-  
+
   ; Set up the frame counter sprites
   ldx #0
   ldy #3
@@ -1132,8 +1131,8 @@ restart:
   lda #3
   sta OAM+$19
   jsr ppu_clear_oam
-  
-  ; Set up the 
+
+  ; Set up the
 
 loop:
   ldx tile_shape
@@ -1276,7 +1275,7 @@ loop:
   sta vram_copydsthi
   lda #$00
   sta vram_copydstlo
-  
+
   ; Choose palette display
   ; 0-2: RGB, no box
   ; 3: white, optional box
@@ -1528,7 +1527,7 @@ loop:
   bcc not_help
     jmp restart
   not_help:
-  
+
   lda new_keys+0
   and #KEY_SELECT
   beq not_invert_grays
@@ -1563,9 +1562,9 @@ loop:
     :
     sta gridlinestype
   is_down:
-  
-  
-  not_updown:  
+
+
+  not_updown:
 
   jsr ppu_wait_vblank
   lda #$3F