;get constants
INCLUDE "constants.asm"
; unused vectors

SECTION "rst 00", ROM0 [$00]
        rst $38
SECTION "rst 08", ROM0 [$08]
        rst $38
SECTION "rst 10", ROM0 [$10]
        rst $38
SECTION "rst 18", ROM0 [$18]
        rst $38
SECTION "rst 28", ROM0 [$20]
        rst $38
SECTION "rst 30", ROM0 [$30]
        rst $38
SECTION "rst 38", ROM0 [$38]
        rst $38

; hardware interrupts

SECTION "vblank", ROM0 [$40]
        jp VBlank
SECTION "hblank", ROM0 [$48]
        rst $38
SECTION "timer", ROM0 [$50]
        reti
SECTION "serial", ROM0 [$58]
        reti
SECTION "joypad", ROM0 [$60]
        reti


SECTION "Entry", ROM0 [$100]
        nop ;go through one cpu cycle
        jp Start ;and jump to start

SECTION "Header", ROM0 [$104]


        ds $150 - $104 ;rgbfix fixes the header for us.

SECTION "Main", ROM0 [$150]
Start::
        di

        ; palettes
        ld  a, %11100100
        ld  [rBGP], a
        ld  a, %11010000
        ld  [rOBP0], a

        xor a
        ld  [rSCX], a ;scrlx
        ld  [rSCY], a ;scrly

        ld  a, %11000111 ; lcdc status
        ld  [rLCDC], a

        ei



        ; set up stack pointer
        ld sp, $dffe


        call WriteDMACodeToHRAM ;dma must be done in HRAM

        ; vblank copy offsets
        lda [H_FIRSTVBLANK], 1


        ;title screen
        ld hl, Title
        ld de, $9000 ;location
        ld bc, $800
        call CopyData
        ld hl, Title+$800
        ld de, $8800 ;location
        ld bc, $100
        call CopyData

        ;tileset
        ld hl, TitleTilemap
        ld de, W_TILEMAP
        ld bc, TitleTilemapEnd-TitleTilemap
        call CopyData



        ld  [$ffff], a
        ld  a, %00000001
        ld  [$ffff], a
        ei
        halt
        xor a
        ld  [H_FIRSTVBLANK], a

        call waitForKey ; wait for A or START to be pressed.



        ; Now we will begin the game.
        ; Load up the map and sprites.

.debugLoop
    jp .debugLoop










waitForKey::
.loop
        halt ;save battery life! <3
        ld  a, [H_JOYNEW]
        and a, %00001001 ; A or START
        jr  z, .loop
        ret



VBlank::
        di
        push af
        call DMARoutine
        pop af
        ei
        reti

; ---------
; lcd functions
; ---------
DisableLCD::
        xor a
        ld  [$ff0f], a
        ld  a, [$ffff]
        ld  b, a
        res 0, a
        ld  [$ffff], a
.waitvblank
        ld  a, [$ff44]
        cp  a, $91
        jr  nz, .waitvblank
        ld  a, [$ff40]
        and a, $7f
        ld  [$ff40], a
        ld  a, b
        ld  [$ffff], a
        ret

EnableLCD::
        ld  a, [$ff40]
        set 7, a
        ld  [$ff40], a
        ret
; -------------
; memory functions
; -------------

ReadJoypad: ;;;
    ld a, [H_JOY]
    ld [H_JOYOLD], a
	ld a,%00100000 ; select direction keys
	ld c,$00
	ld [rJOYP],a
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	cpl ; complement the result so that a set bit indicates a pressed key
	and a,%00001111
	swap a ; put direction keys in upper nibble
	ld b,a
	ld a,%00010000 ; select button keys
	ld [rJOYP],a
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	ld a,[rJOYP]
	cpl ; complement the result so that a set bit indicates a pressed key
	and a,%00001111
	or b ; put button keys in lower nibble
	ld [$fff8],a ; save joypad state
	ld a,%00110000 ; unselect all keys
	ld [rJOYP],a

	ld a, [H_JOY]
	ld b, a
	ld a, [H_JOYOLD]
	xor $ff
	and b
	ld [H_JOYNEW], a

	ret

WriteDMACodeToHRAM::
        ld  c, $80
        ld  b, $a
        ld  hl, DMARoutine
.copyLoop
        ld  a, [hli]
        ld  [$ff00+c], a
        inc c
        dec b
        jr  nz, .copyLoop
        ret

DMARoutine::
        ld  a, W_OAM >> 8
        ld  [$ff00+$46], a ; start DMA
        ld  a, $28
.waitLoop
        dec a
        jr  nz, .waitLoop
        ret


CopyData:: ;memcpy routine
        ld  a, [hli]
        ld  [de], a
        inc de
        dec bc
        ld  a, c
        or  b
        jr  nz, CopyData
        ret

FillMemory::
.loop
        ld  [hli], a
        dec b
        jr  nz, .loop
        ret

ClearOAM::
        xor a
        ld  hl, W_OAM
        ld  b, 4*$28
        call FillMemory
        ret




;includes

INCLUDE "title.z80"
INCLUDE "tileset.z80"



;internal RAM
SECTION "IntRAM",BSS[$C000]

player_xpos
ds      1
player_ypos
ds      1
player_tile:
ds      1
player_flags:
ds      1


SECTION "highRAM",BSS[$C0A0]