ALTTP One Mind v1.1

; ALTTP One-Mind hack: causes the current player in control of Link to switch every so often.
;  In places where this does not occur (e.g. title screen), both controllers are registered.
; Save this text file as an ASM file and patch it to your rom with Asar.
; A few extra options for adjusting timing are below.

;;;; Timing

!count_silent   =   $08 ; Number of silent ticks before audible ones
!count_audible  =   $04 ; Number of audible ticks before the controller switches
!tickTiming     =   $1F ; Number of frames between ticks (valid: 01, 03, 07, 0F, 1F, 3F, 7F, FF)

; Hard mode: set silent to 1, audible to 1.

;;;; SFX

!SFX_Tick       =   $06     ; SFX values for the tick noise.
!SFXIO_Tick     =   $012E
!SFX_Switch     =   $25     ; SFX values for when the players switch.
!SFXIO_Switch   =   $012F


;;;; Technical

!freeram    =   $7F9000     ; 2 bytes of free ram to use.


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Code begins; don't touch it unless you know what you're doing.

!active     = !freeram      ; 1 byte - currently active player
!ticks      = !freeram+1    ; 1 byte - counter for the number of ticks so far


org $0083D1
    autoclean JSL OneMind
    BRA $05

freecode
OneMind:
    PHB : PHK : PLB
    JSR Main
    PLB
    RTL

Main:
    ; Check whether in a mode we allow switching in.
    ; If not, register both controllers.
    LDA $10
    CMP #$07    ; normal play - interior
    BEQ .acceptable
    CMP #$09    ; normal play - exterior
    BEQ .acceptable
    CMP #$0E    ; normal play - text box, pause screen, map screen
    BEQ .acceptable
    BRA SetBothControllers
  .acceptable

    ; Good to go.
    LDA $1A
    AND #!tickTiming
    BNE SetControllers
    LDA !ticks
    INC
    CMP #!count_silent
    BCC .silentTick
    CMP #!count_silent+!count_audible
    BCC .tick
    JSR SwitchPlayers
    BRA SetControllers
  .tick
    LDY #!SFX_Tick
    STY !SFXIO_Tick
  .silentTick
    STA !ticks

 SetControllers:
    LDA !active
    AND #$01
    BNE .c2
  .c1
    LDA $4218
    STA $00
    LDA $4219
    RTS
  .c2
    LDA $421A
    STA $00
    LDA $421B
    RTS

 SetBothControllers:
    LDA $4218
    ORA $421A
    STA $00
    LDA $4219
    ORA $421B
    RTS



SwitchPlayers:
    LDA #$00
    STA !ticks
    LDA !active
    INC
    STA !active
    LDA #!SFX_Switch
    STA !SFXIO_Switch

    REP #$30
    LDA $7EF35B
    AND #$00FF
    TAX
    LDA !active
    AND #$0001
    BNE .p2pal
    LDA $1BEC06,x
    AND #$00FF
    ASL
    ADC #$D308
    STA $00
    LDA #$001B
    STA $02
    BRA .paletteUpload
  .p2pal
    TXA
    ASL
    TAX
    LDA P2Palettes,x
    STA $00
    LDA.w #P2PalA>>16
    STA $02

  .paletteUpload
    LDY #$000E
    LDX #$01E2

  - LDA [$00]
    STA $7EC300,X
    STA $7EC500,X
    INC $00
    INC $00
    INX
    INX
    DEY
    BPL -
    SEP #$30
    INC $15
    RTS


P2Palettes:
    dw P2PalA,P2PalB,P2PalC

; Player 2 palette data. Feel free to mess with it if you know how.
P2PalA:     ; green mail
    dw $7FFF,$237E,$11B7,$369E,$14A5
    dw $01FF,$1078,$599D,$1CF3,$2CFC
    dw $0415,$101C,$2A5C,$1571,$7A18
P2PalB:     ; blue mail
    dw $7FFF,$237E,$11B7,$369E,$14A5
    dw $01FF,$1078,$599D,$0A1D,$2B3D
    dw $6132,$7E17,$2A5C,$1199,$7A18
P2PalC:     ; red mail
    dw $7FFF,$237E,$11B7,$369E,$14A5
    dw $01FF,$1078,$599D,$62C2,$73EB
    dw $2B28,$3FCB,$2A5C,$2227,$7A18