// Conversion of https://gbdev.io/gb-asm-tutorial/assets/hello-world.asm

const TILE_BLOCK_2: u16 = $9000
const TILE_MAP_0: u16 = $9800
const NR52: u16 = $FF26
const LCDC: u16 = $FF40
const LY: u16 = $FF44
const BGP: u16 = $FF47

const LCDCF_ON: u8 = %10000000
const LCDCF_BGON: u8 = %00000001

fn main() {
  // Shut down audio circuitry
  a = 0
  [NR52] = a

  // Do not turn the LCD off outside of VBlank
  loop {
    a = [LY]
    f = a - 144
    if nc {
      break
    }
  }

  // Turn the LCD off
  a = 0
  [LCDC] = a

  // Copy the tile data
	de = Tiles
	hl = TILE_BLOCK_2
	bc = size_of!(Tiles)
  copy_data()

  // Copy the tilemap
	de = Tilemap
	hl = TILE_MAP_0
	bc = size_of!(Tilemap)
  copy_data()

  // Turn the LCD on
  a = LCDCF_ON | LCDCF_BGON
  [LCDC] = a

  // During the first (blank) frame, initialize display registers
  a = %11_10_01_00
  [BGP] = a

  loop {}
}

// Copies `bc` bytes from `de` to `hl`
// 
// Assumes `bc` starts as non-zero!
fn copy_data() {
  loop {
    a = [de]
    [hl++] = a
    de++
    bc--
    a = b | c
    if z {
      return
    }
  }
}

static Tiles: [u8] = [
	$00,$ff, $00,$ff, $00,$ff, $00,$ff, $00,$ff, $00,$ff, $00,$ff, $00,$ff,
	$00,$ff, $00,$80, $00,$80, $00,$80, $00,$80, $00,$80, $00,$80, $00,$80,
	$00,$ff, $00,$7e, $00,$7e, $00,$7e, $00,$7e, $00,$7e, $00,$7e, $00,$7e,
	$00,$ff, $00,$01, $00,$01, $00,$01, $00,$01, $00,$01, $00,$01, $00,$01,
	$00,$ff, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00,
	$00,$ff, $00,$7f, $00,$7f, $00,$7f, $00,$7f, $00,$7f, $00,$7f, $00,$7f,
	$00,$ff, $03,$fc, $00,$f8, $00,$f0, $00,$e0, $20,$c0, $00,$c0, $40,$80,
	$00,$ff, $c0,$3f, $00,$1f, $00,$0f, $00,$07, $04,$03, $00,$03, $02,$01,
	$00,$80, $00,$80, $7f,$80, $00,$80, $00,$80, $7f,$80, $7f,$80, $00,$80,
	$00,$7e, $2a,$7e, $d5,$7e, $2a,$7e, $54,$7e, $ff,$00, $ff,$00, $00,$00,
	$00,$01, $00,$01, $ff,$01, $00,$01, $01,$01, $fe,$01, $ff,$01, $00,$01,
	$00,$80, $80,$80, $7f,$80, $80,$80, $00,$80, $ff,$80, $7f,$80, $80,$80,
	$00,$7f, $2a,$7f, $d5,$7f, $2a,$7f, $55,$7f, $ff,$00, $ff,$00, $00,$00,
	$00,$ff, $aa,$ff, $55,$ff, $aa,$ff, $55,$ff, $fa,$07, $fd,$07, $02,$07,
	$00,$7f, $2a,$7f, $d5,$7f, $2a,$7f, $55,$7f, $aa,$7f, $d5,$7f, $2a,$7f,
	$00,$ff, $80,$ff, $00,$ff, $80,$ff, $00,$ff, $80,$ff, $00,$ff, $80,$ff,
	$40,$80, $00,$80, $7f,$80, $00,$80, $00,$80, $7f,$80, $7f,$80, $00,$80,
	$00,$3c, $02,$7e, $85,$7e, $0a,$7e, $14,$7e, $ab,$7e, $95,$7e, $2a,$7e,
	$02,$01, $00,$01, $ff,$01, $00,$01, $01,$01, $fe,$01, $ff,$01, $00,$01,
	$00,$ff, $80,$ff, $50,$ff, $a8,$ff, $50,$ff, $a8,$ff, $54,$ff, $a8,$ff,
	$7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80,
	$ff,$00, $ff,$00, $ff,$00, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e,
	$ff,$01, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $fe,$01,
	$7f,$80, $ff,$80, $7f,$80, $ff,$80, $7f,$80, $ff,$80, $7f,$80, $ff,$80,
	$ff,$00, $ff,$00, $ff,$00, $aa,$7f, $d5,$7f, $aa,$7f, $d5,$7f, $aa,$7f,
	$f8,$07, $f8,$07, $f8,$07, $80,$ff, $00,$ff, $aa,$ff, $55,$ff, $aa,$ff,
	$7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $ff,$80, $7f,$80, $ff,$80,
	$d5,$7f, $aa,$7f, $d5,$7f, $aa,$7f, $d5,$7f, $aa,$7f, $d5,$7f, $aa,$7f,
	$d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $eb,$3c,
	$54,$ff, $aa,$ff, $54,$ff, $aa,$ff, $54,$ff, $aa,$ff, $54,$ff, $aa,$ff,
	$7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $00,$ff,
	$d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $2a,$ff,
	$ff,$01, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $80,$ff,
	$7f,$80, $ff,$80, $7f,$80, $ff,$80, $7f,$80, $ff,$80, $7f,$80, $aa,$ff,
	$ff,$00, $ff,$00, $ff,$00, $ff,$00, $ff,$00, $ff,$00, $ff,$00, $2a,$ff,
	$ff,$01, $fe,$01, $ff,$01, $fe,$01, $fe,$01, $fe,$01, $fe,$01, $80,$ff,
	$7f,$80, $ff,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $7f,$80, $00,$ff,
	$fe,$01, $fe,$01, $fe,$01, $fe,$01, $fe,$01, $fe,$01, $fe,$01, $80,$ff,
	$3f,$c0, $3f,$c0, $3f,$c0, $1f,$e0, $1f,$e0, $0f,$f0, $03,$fc, $00,$ff,
	$fd,$03, $fc,$03, $fd,$03, $f8,$07, $f9,$07, $f0,$0f, $c1,$3f, $82,$ff,
	$55,$ff, $2a,$7e, $54,$7e, $2a,$7e, $54,$7e, $2a,$7e, $54,$7e, $00,$7e,
	$01,$ff, $00,$01, $01,$01, $00,$01, $01,$01, $00,$01, $01,$01, $00,$01,
	$54,$ff, $ae,$f8, $50,$f0, $a0,$e0, $60,$c0, $80,$c0, $40,$80, $40,$80,
	$55,$ff, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00,
	$55,$ff, $6a,$1f, $05,$0f, $02,$07, $05,$07, $02,$03, $03,$01, $02,$01,
	$54,$ff, $80,$80, $00,$80, $80,$80, $00,$80, $80,$80, $00,$80, $00,$80,
	$55,$ff, $2a,$1f, $0d,$07, $06,$03, $01,$03, $02,$01, $01,$01, $00,$01,
	$55,$ff, $2a,$7f, $55,$7f, $2a,$7f, $55,$7f, $2a,$7f, $55,$7f, $00,$7f,
	$55,$ff, $aa,$ff, $55,$ff, $aa,$ff, $55,$ff, $aa,$ff, $55,$ff, $00,$ff,
	$15,$ff, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00, $00,$00,
	$55,$ff, $6a,$1f, $0d,$07, $06,$03, $01,$03, $02,$01, $03,$01, $00,$01,
	$54,$ff, $a8,$ff, $54,$ff, $a8,$ff, $50,$ff, $a0,$ff, $40,$ff, $00,$ff,
	$00,$7e, $2a,$7e, $d5,$7e, $2a,$7e, $54,$7e, $ab,$76, $dd,$66, $22,$66,
	$00,$7c, $2a,$7e, $d5,$7e, $2a,$7e, $54,$7c, $ff,$00, $ff,$00, $00,$00,
	$00,$01, $00,$01, $ff,$01, $02,$01, $07,$01, $fe,$03, $fd,$07, $0a,$0f,
	$00,$7c, $2a,$7e, $d5,$7e, $2a,$7e, $54,$7e, $ab,$7e, $d5,$7e, $2a,$7e,
	$00,$ff, $a0,$ff, $50,$ff, $a8,$ff, $54,$ff, $a8,$ff, $54,$ff, $aa,$ff,
	$dd,$62, $bf,$42, $fd,$42, $bf,$40, $ff,$00, $ff,$00, $f7,$08, $ef,$18,
	$ff,$00, $ff,$00, $ff,$00, $ab,$7c, $d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e,
	$f9,$07, $fc,$03, $fd,$03, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $fe,$01,
	$d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $ab,$7e, $d5,$7e, $ab,$7c,
	$f7,$18, $eb,$1c, $d7,$3c, $eb,$3c, $d5,$3e, $ab,$7e, $d5,$7e, $2a,$ff,
	$ff,$01, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $fe,$01, $ff,$01, $a2,$ff,
	$7f,$c0, $bf,$c0, $7f,$c0, $bf,$e0, $5f,$e0, $af,$f0, $57,$fc, $aa,$ff,
	$ff,$01, $fc,$03, $fd,$03, $fc,$03, $f9,$07, $f0,$0f, $c1,$3f, $82,$ff,
	$55,$ff, $2a,$ff, $55,$ff, $2a,$ff, $55,$ff, $2a,$ff, $55,$ff, $00,$ff,
	$45,$ff, $a2,$ff, $41,$ff, $82,$ff, $41,$ff, $80,$ff, $01,$ff, $00,$ff,
	$54,$ff, $aa,$ff, $54,$ff, $aa,$ff, $54,$ff, $aa,$ff, $54,$ff, $00,$ff,
	$15,$ff, $2a,$ff, $15,$ff, $0a,$ff, $15,$ff, $0a,$ff, $01,$ff, $00,$ff,
	$01,$ff, $80,$ff, $01,$ff, $80,$ff, $01,$ff, $80,$ff, $01,$ff, $00,$ff,
]

static Tilemap: [u8] = [
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $01, $02, $03, $01, $04, $03, $01, $05, $00, $01, $05, $00, $06, $04, $07, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $08, $09, $0a, $0b, $0c, $0d, $0b, $0e, $0f, $08, $0e, $0f, $10, $11, $12, $13, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $14, $15, $16, $17, $18, $19, $1a, $1b, $0f, $14, $1b, $0f, $14, $1c, $16, $1d, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $1e, $1f, $20, $21, $22, $23, $24, $22, $25, $1e, $22, $25, $26, $22, $27, $1d, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $01, $28, $29, $2a, $2b, $2c, $2d, $2b, $2e, $2d, $2f, $30, $2d, $31, $32, $33, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $08, $34, $0a, $0b, $11, $0a, $0b, $35, $36, $0b, $0e, $0f, $08, $37, $0a, $38, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $14, $39, $16, $17, $1c, $16, $17, $3a, $3b, $17, $1b, $0f, $14, $3c, $16, $1d, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $1e, $3d, $3e, $3f, $22, $27, $21, $1f, $20, $21, $22, $25, $1e, $22, $40, $1d, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $41, $42, $43, $44, $30, $33, $41, $45, $43, $41, $30, $43, $41, $30, $33, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
	$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,  0,0,0,0,0,0,0,0,0,0,0,0,
]