LatchController:
  LDA #$01
  STA $4016
  LDA #$00
  STA $4016     ;  tell both the controllers to latch buttons

ButtonA:
  LDA $4016       ; player 1 - A
  AND #%00000001  ; look only at bit 0
  BNE ButtonB

; Button stuff here

ButtonB:
  LDA $4016       ; player 1 - B
  AND #%00000001  ; look only at bit 0
  BNE SelectButton

; Button stuff here

SelectButton:
  LDA $4016       ; player 1 - Select
  AND #%00000001  ; look only at bit 0
  BNE StartButton

; Button stuff here

StartButton:
  LDA $4016       ; player 1 - Start
  AND #%00000001  ; look only at bit 0
  BNE UpButton

; Button stuff here

UpButton:
  LDA $4016       ; player 1 - Up
  AND #%00000001  ; look only at bit 0
  BNE DownButton

; Button stuff here

DownButton:
  LDA $4016       ; player 1 - Down
  AND #%00000001  ; look only at bit 0
  BNE LeftButton

; Button stuff here

LeftButton:
  LDA $4016       ; player 1 - Left
  AND #%00000001  ; look only at bit 0
  BNE RightButton
  LDA $0203       ; load sprite X position
  CLC             ; make sure the carry flag is clear
  ADC #$01        ; A = A + 1
  STA $0203       ; save sprite X position
  LDA $0207       ; load sprite X position
  CLC             ; make sure the carry flag is clear
  ADC #$01        ; A = A + 1
  STA $0207       ; save sprite X position
  LDA $020B       ; load sprite X position
  CLC             ; make sure the carry flag is clear
  ADC #$01        ; A = A + 1
  STA $020B       ; save sprite X position
  LDA $020F       ; load sprite X position
  CLC             ; make sure the carry flag is clear
  ADC #$01        ; A = A + 1
  STA $020F       ; save sprite X position
  LDA $0213
  CLC
  ADC #$01
  STA $0213
  LDA $0217
  CLC
  ADC #$01
  STA $0217
  LDA $021B
  CLC
  ADC #$01
  STA $021B
  LDA $021F
  CLC
  ADC #$01
  STA $021F

RightButton:
  LDA $4016       ; player 1 - Right
  AND #%00000001  ; look only at bit 0
  BNE NotRightButton
  LDA $0203       ; load sprite X position
  SEC             ; make sure carry flag is set
  SBC #$01        ; A = A - 1
  STA $0203       ; save sprite X position
  LDA $0207       ; load sprite X position
  SEC             ; make sure carry flag is set
  SBC #$01        ; A = A - 1
  STA $0207       ; save sprite X position
  LDA $020B       ; load sprite X position
  SEC             ; make sure carry flag is set
  SBC #$01        ; A = A - 1
  STA $020B       ; save sprite X position
  LDA $020F       ; load sprite X position
  SEC             ; make sure carry flag is set
  SBC #$01        ; A = A - 1
  STA $020F       ; save sprite X position
  LDA $0213
  CLC
  ADC #$01
  STA $0213
  LDA $0217
  CLC
  ADC #$01
  STA $0217
  LDA $021B
  CLC
  ADC #$01
  STA $021B
  LDA $021F
  CLC
  ADC #$01
  STA $021F

NotRightButton:
  JMP ButtonA

  RTI             ; return from interrupt

;;;;;;;;;;;;;;


;;;;;;;;;;;;;;



  .bank 1
  .org $E000
palette:
  .db $22,$0F,$27,$26,  $22,$0F,$16,$26,  $22,$30,$21,$0F,  $22,$27,$17,$0F   ;;background palette
  .db $22,$0F,$27,$1A,  $22,$0F,$27,$26,  $22,$1C,$15,$14,  $22,$02,$38,$3C   ;;sprite palette

sprites:
     ;vert tile attr horiz
  .db $80, $00, $00, $80   ;sprite 0
  .db $80, $01, $00, $88   ;sprite 1
  .db $88, $10, $00, $80   ;sprite 2
  .db $88, $11, $00, $88   ;sprite 3
  .db $90, $20, $00, $80   ;sprite 4
  .db $90, $21, $00, $88   ;sprite 5
  .db $98, $30, $00, $80   ;sprite 6
  .db $98, $31, $00, $88   ;sprite 7