BUTTONS .rs 1 ; currently pressed buttons
BUTTONS_TMP .rs 1 ; temporary variable for buttons
BUTTONS_HOLD_TIME .rs 1 ; up/down/left/right buttons hold time
KONAMI_CODE_STATE .rs 1 ; Konami Code state

  .if GAMES_COUNT >= 11
MAXIMUM_SCROLL .equ GAMES_COUNT - 11
  .else
MAXIMUM_SCROLL .equ 0
  .endif

  ; controller reading, two times
read_controller:
  pha
  tya
  pha
  txa
  pha
  jsr .real ; first read
  ldx <BUTTONS_TMP
  jsr .real ; second read
  cpx <BUTTONS_TMP ; lets compare values
  bne .end ; ignore it if not equal
  stx <BUTTONS ; storing value
  txa
  and #%11110000 ; up/down/left/right
  beq .no_up_down ; is pressed?
  inc <BUTTONS_HOLD_TIME ; increasing hold time
  lda <BUTTONS_HOLD_TIME
  cmp #BUTTON_REPEAT_FRAMES ; is it holding long enought?
  bcc .end ; no
  lda #0 ; yes, it's long enought, so lets "release" buttons
  sta <BUTTONS
  lda #BUTTON_REPEAT_FRAMES - 10 ; autorepeat time = 10
  sta <BUTTONS_HOLD_TIME
  jmp .end
.no_up_down:
  lda #0 ; reset hold time
  sta <BUTTONS_HOLD_TIME
.end:
  pla
  tax
  pla
  tay
  pla
  rts

  ; real controller read, stores buttons to BUTTONS_TMP
.real:
  lda #1
  sta JOY1
  lda #0
  sta JOY1
  ldy #8
.read_button:
  lda JOY1
  and #$03
  cmp #$01
  ror <BUTTONS_TMP
  dey
  bne .read_button
  rts

  ; check buttons state and do some action
buttons_check:
  ; if buttons are not pressed at all return immediately
  lda <BUTTONS
  cmp #$00
  bne .start_check
  rts
.start_check:
  jsr konami_code_check
.button_a:
  lda <BUTTONS
  and #%00000001
  beq .button_b
  jmp start_game

.button_b:
  lda <BUTTONS
  and #%00000010
  beq .button_start
  ; nothing to do
  jmp .button_end

.button_start:
  lda <BUTTONS
  and #%00001000
  beq .button_up
  jmp start_game

.button_up:
  lda <BUTTONS
  and #%00010000
  beq .button_down
  .if ENABLE_SOUND!=0
  jsr bleep
  .endif
  lda <SELECTED_GAME
  sec
  sbc #1
  sta <SELECTED_GAME
  lda <SELECTED_GAME+1
  sbc #0
  sta <SELECTED_GAME+1
  bmi .button_up_ovf
  jsr check_separator_up
  jmp .button_end
.button_up_ovf:
  .if GAMES_COUNT < WRAP_GAMES
  lda #LOW(GAMES_COUNT - 1)
  sta <SELECTED_GAME
  lda #HIGH(GAMES_COUNT - 1)
  sta <SELECTED_GAME+1
  .else
  jsr screen_wrap_up
  .endif
  jsr check_separator_up
  jmp .button_end

.button_down:
  lda <BUTTONS
  and #%00100000
  beq .button_left
  .if ENABLE_SOUND!=0
  jsr bleep
  .endif
  lda <SELECTED_GAME
  clc
  adc #1
  sta <SELECTED_GAME
  lda <SELECTED_GAME+1
  adc #0
  sta <SELECTED_GAME+1
  cmp #HIGH(GAMES_COUNT)
  bne .button_down_not_ovf
  lda <SELECTED_GAME
  cmp #LOW(GAMES_COUNT)
  beq .button_down_ovf
.button_down_not_ovf:
  jsr check_separator_down
  jmp .button_end
.button_down_ovf:
  .if GAMES_COUNT < WRAP_GAMES
  lda #0
  sta <SELECTED_GAME
  sta <SELECTED_GAME+1
  sta <SCROLL_LINES_TARGET
  sta <SCROLL_LINES_TARGET+1
  .else
  jsr screen_wrap_down
  .endif
  jsr check_separator_down
  jmp .button_end

.button_left:
  lda <BUTTONS
  and #%01000000
  beq .button_right
  lda <SELECTED_GAME
  bne .button_left_bleep
  lda <SELECTED_GAME+1
  bne .button_left_bleep
  jmp .button_right
.button_left_bleep:
  .if ENABLE_SOUND!=0
  jsr bleep
  .endif
  lda <SCROLL_LINES_TARGET
  sec
  sbc #10
  sta <SCROLL_LINES_TARGET
  lda <SCROLL_LINES_TARGET+1
  sbc #0
  sta <SCROLL_LINES_TARGET+1
  bmi .button_left_ovf
  jmp .button_left2
.button_left_ovf:
  lda #0
  sta <SCROLL_LINES_TARGET
  sta <SCROLL_LINES_TARGET+1
.button_left2:
  lda <SELECTED_GAME
  sec
  sbc #10
  sta <SELECTED_GAME
  lda <SELECTED_GAME+1
  sbc #0
  sta <SELECTED_GAME+1
  bmi .button_left_ovf2
  jsr check_separator_down
  jmp .button_end
.button_left_ovf2:
  lda #0
  sta <SELECTED_GAME
  sta <SELECTED_GAME+1
  jsr check_separator_down
  jmp .button_end

.button_right:
  lda <BUTTONS
  and #%10000000
  bne .button_right_check
  jmp .button_end
.button_right_check:
  ; need to bleep if it's not last game
  lda <SELECTED_GAME
  clc
  adc #1
  cmp #LOW(GAMES_COUNT)
  bne .button_right_bleep
  lda <SELECTED_GAME
  clc
  adc #1
  lda <SELECTED_GAME+1
  adc #0
  cmp #HIGH(GAMES_COUNT)
  bne .button_right_bleep
  jmp .button_end
.button_right_bleep:
  .if ENABLE_SOUND!=0
  jsr bleep
  .endif
  lda <SCROLL_LINES_TARGET
  clc
  adc #10
  sta <SCROLL_LINES_TARGET
  lda <SCROLL_LINES_TARGET+1
  adc #0
  sta <SCROLL_LINES_TARGET+1
  ; scrolling overflow test
  lda <SCROLL_LINES_TARGET
  sec
  sbc #LOW(MAXIMUM_SCROLL)
  lda <SCROLL_LINES_TARGET+1
  sbc #HIGH(MAXIMUM_SCROLL)
  bcs .button_right_ovf
.button_right_not_ovf:
  jmp .button_right2
.button_right_ovf:
  lda #LOW(MAXIMUM_SCROLL)
  sta <SCROLL_LINES_TARGET
  lda #HIGH(MAXIMUM_SCROLL)
  sta <SCROLL_LINES_TARGET+1
.button_right2:
  lda <SELECTED_GAME
  clc
  adc #10
  sta <SELECTED_GAME
  lda <SELECTED_GAME+1
  adc #0
  sta <SELECTED_GAME+1
  ; selected game overflow test
  lda <SELECTED_GAME
  sec
  sbc #LOW(GAMES_COUNT)
  lda <SELECTED_GAME+1
  sbc #HIGH(GAMES_COUNT)
  bcs .button_right_ovf2
.button_right_not_ovf2:
  jsr check_separator_up
  jmp .button_end
.button_right_ovf2:
  lda #LOW(GAMES_COUNT)
  sec
  sbc #1
  sta <SELECTED_GAME
  lda #HIGH(GAMES_COUNT)
  sbc #0
  sta <SELECTED_GAME+1
  jsr check_separator_up
  jmp .button_end

.button_none:
  ; this code shouldn't never ever be executed
  rts

.button_end:
  jsr set_scroll_targets ; updating cursor targets
  ; saving last cursor position
  .if (INSTANT_STATE_SAVE!=0) & (ENABLE_LAST_GAME_SAVING!=0)
  jsr save_state
  .endif
  ; waiting until buttons released
  jsr wait_buttons_not_pressed
  rts

; need to skip separator when scrolling upwards
check_separator_down:
  lda <SELECTED_GAME+1
  jsr select_prg_bank
  ldx <SELECTED_GAME
  lda loader_data_game_flags, x
  and #$80
  beq check_separator_down_end
  lda <SELECTED_GAME
  clc
  adc #1
  sta <SELECTED_GAME
  lda <SELECTED_GAME+1
  adc #0
  sta <SELECTED_GAME+1
  cmp #HIGH(GAMES_COUNT)
  bne check_separator_down
  lda <SELECTED_GAME
  cmp #LOW(GAMES_COUNT)
  bne check_separator_down
  .if GAMES_COUNT < WRAP_GAMES
  lda #0
  sta <SELECTED_GAME
  sta <SELECTED_GAME+1
  sta <SCROLL_LINES_TARGET
  sta <SCROLL_LINES_TARGET+1
  .else
  jsr screen_wrap_down
  .endif
  jmp check_separator_down
check_separator_down_end:
  rts

; need to skip separator when scrolling downwards
check_separator_up:
  lda <SELECTED_GAME+1
  jsr select_prg_bank
  ldx <SELECTED_GAME
  lda loader_data_game_flags, x
  and #$80
  beq check_separator_up_end
  lda <SELECTED_GAME
  sec
  sbc #1
  sta <SELECTED_GAME
  lda <SELECTED_GAME+1
  sbc #0
  sta <SELECTED_GAME+1
  bpl check_separator_up
  .if GAMES_COUNT < WRAP_GAMES
  lda #LOW(GAMES_COUNT - 1)
  sta <SELECTED_GAME
  lda #HIGH(GAMES_COUNT - 1)
  sta <SELECTED_GAME+1
  .else
  jsr screen_wrap_up
  .endif
  jmp check_separator_up
check_separator_up_end:
  rts

  ; waiting for button release
wait_buttons_not_pressed:
  jsr waitblank ; waiting for v-blank
  lda <BUTTONS
  bne wait_buttons_not_pressed
  rts

  ; waiting for button release, really
wait_buttons_really_not_pressed:
  jsr waitblank ; waiting for v-blank
  lda <BUTTONS
  bne wait_buttons_really_not_pressed
  lda BUTTONS_HOLD_TIME
  bne wait_buttons_really_not_pressed
  rts

konami_code_check:
  ldy <KONAMI_CODE_STATE
  lda konami_code, y
  cmp <BUTTONS
  bne konami_code_check_fail
  iny
  jmp konami_code_check_end
konami_code_check_fail:
  ldy #0
  lda konami_code ; in case when newpressed button is first button of code
  cmp <BUTTONS
  bne konami_code_check_end
  iny
konami_code_check_end:
  sty <KONAMI_CODE_STATE
  rts

konami_code:
  .db $10, $10, $20, $20, $40, $80, $40, $80, $02, $01
konami_code_length:
  .db 10