Optimized Untitled

calculatePalette:
  ; Get the current line
  ld b, 0
  ld a, [rLY]
  ld c, a

  ; Get sin(Ly/PI) or SinLyPiTable[b] if you want to see it as an array.
  ld hl, SinLyPiTable
  add hl, bc
  ld d, [hl]


  ; Multiply by 2 or 4
  ld a, [wScale]
  ld b, a
  and a
  ld a, d
  jr z, _noScale
_multiply:
  add a, a
  dec b
  jr nz, _multiply

  jr _noDownScale

_noScale:
  ; Scale back down ( / 8)
  and %11111000
  rrca
  rrca
  rrca
_noDownScale:

  ; Use the result to change the palette
  and %00000011
  cpl
  ldh [< rBGP], a
ret