Teleport when pressing A or B, with sound effect

level13C:        ; teleport when pressing A or B, with sound effect
    LDA #$FF     ;\ disable pausing
    STA $13D3    ;/
    LDA $15      ; load controller data 1
    AND #$80     ; filter out only "A or B" bit
    BNE TeleportToScreenExit

    STZ $15      ;\
    STZ $16      ;| zero out controller data
    STZ $17      ;|
    STZ $18      ;/
  DontTeleport:
    RTS

  TeleportToScreenExit:
    LDA #$15      ;\ play sound effect (path revealed)
    STA $1DFC     ;/
    LDA #$06      ;\
    STA $71       ;| teleport
    STZ $88       ;|
    STZ $89       ;/
    RTS