1 files changed, 615 insertions, 0 deletions
diff --git a/home/vcopy.asm b/home/vcopy.asm
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+INCLUDE "constants.asm"
+INCLUDE "vram.asm"
+
+SECTION "Copy Routines used by VBlank ISR", ROM0[$123a]
+
+; This function redraws a BG row of height 2 or a BG column of width 2.
+; One of its main uses is redrawing the row or column that will be exposed upon
+; scrolling the BG when the player takes a step. Redrawing only the exposed
+; row or column is more efficient than redrawing the entire screen.
+; However, this function is also called repeatedly to redraw the whole screen
+; when necessary. It is also used in trade animation and elevator code.
+; This also implements the flashlight drawing distance effect, which takes
+; multiple frames in either direction to complete
+RedrawRowOrColumn:: ; 123a (0:123a)
+	ldh a, [hRedrawRowOrColumnMode]
+	and a
+	ret z
+	cp $03
+	jr nc, .flashlight_effect
+	ld b, a
+	xor a
+	ldh [hRedrawRowOrColumnMode], a
+	dec b
+	jr nz, .redrawRow
+.redrawColumn
+	ld hl, wRedrawRowOrColumnSrcTiles
+	ldh a, [hRedrawRowOrColumnDest]
+	ld e, a
+	ldh a, [hRedrawRowOrColumnDest + 1]
+	ld d, a
+	ld c, SCREEN_HEIGHT
+.col_loop
+	ld a, [hli]
+	ld [de], a
+	inc de
+	ld a, [hli]
+	ld [de], a
+	ld a, BG_MAP_WIDTH - 1
+	add e
+	ld e, a
+	jr nc, .noCarry
+	inc d
+.noCarry
+; the following 4 lines wrap us from bottom to top if necessary
+	ld a, d
+	and HIGH(vBGMap1 - vBGMap0 - $01)
+	or HIGH(vBGMap0)
+	ld d, a
+	dec c
+	jr nz, .col_loop
+	xor a
+	ldh [hRedrawRowOrColumnMode], a
+	ret
+.redrawRow
+	ld hl, wRedrawRowOrColumnSrcTiles
+	ldh a, [hRedrawRowOrColumnDest]
+	ld e, a
+	ldh a, [hRedrawRowOrColumnDest + 1]
+	ld d, a
+	push de
+	call .DrawHalf
+	pop de
+	ld a, BG_MAP_WIDTH ; width of VRAM background map
+	add e
+	ld e, a
+	; fall through and draw lower half
+	
+.DrawHalf
+	ld c, SCREEN_WIDTH / 2
+.row_loop
+	ld a, [hli]
+	ld [de], a
+	inc de
+	ld a, [hli]
+	ld [de], a
+	ld a, e
+	inc a
+; the following 6 lines wrap us from the right edge to the left edge if necessary
+	and BG_MAP_WIDTH - 1            ; mask lower address bits
+	ld b, a
+	ld a, e
+	and ($FF ^ (BG_MAP_WIDTH - 1))  ; mask upper address bits
+	or b
+	ld e, a
+	dec c
+	jr nz, .row_loop
+	ret
+.flashlight_effect
+	dec a
+	dec a
+	dec a
+	ld c, a
+	ld b, $00
+	ld hl, .flashlight_effect_table
+	add hl, bc
+	add hl, bc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	jp hl
+.flashlight_effect_table
+	dw RedrawFlashlightRow0    ; $1310
+	dw RedrawFlashlightRow0    ; $1310
+	dw RedrawFlashlightColumn0 ; $12C3
+	dw RedrawFlashlightColumn0 ; $12C3
+	dw RedrawFlashlightRow1    ; $1329
+	dw RedrawFlashlightRow1    ; $1329
+	dw RedrawFlashlightColumn1 ; $12DC
+	dw RedrawFlashlightColumn1 ; $12DC
+	dw RedrawFlashlightRow2    ; $1335
+	dw RedrawFlashlightRow2    ; $1335
+	dw RedrawFlashlightColumn2 ; $12E8
+	dw RedrawFlashlightColumn2 ; $12E8
+	dw RedrawFlashlightRow3    ; $134E
+	dw RedrawFlashlightRow3    ; $134E
+	dw RedrawFlashlightColumn3 ; $1301
+	dw RedrawFlashlightColumn3 ; $1301
+	
+RedrawFlashlightColumn0:: ; 12c3 (0:12c3)
+	ldh a, [hSCX]
+	and $07
+	ret nz        ; wait till we moved one complete tile in X
+	ld a, [wRedrawFlashlightDst0]
+	ld e, a
+	ld a, [wRedrawFlashlightDst0 + 1]
+	ld d, a
+	ld a, [wRedrawFlashlightSrc0]
+	ld l, a
+	ld a, [wRedrawFlashlightSrc0 + 1]
+	ld h, a
+	call _RedrawFlashlightColumn
+	ret
+
+RedrawFlashlightColumn1:: ; 12dc (0:12dc)
+	ld a, [wRedrawFlashlightBlackDst0]
+	ld e, a
+	ld a, [wRedrawFlashlightBlackDst0 + 1]
+	ld d, a
+	call _RedrawFlashlightColumnBlack
+	ret
+; 0x12e8
+
+RedrawFlashlightColumn2:: ; 12e8 (0:12e8)
+	ldh a, [hSCX]
+	and $0f
+	ret nz        ; wait till we moved two complete tiles in X
+	ld a, [wRedrawFlashlightDst1]
+	ld e, a
+	ld a, [wRedrawFlashlightDst1 + 1]
+	ld d, a
+	ld a, [wRedrawFlashlightSrc1]
+	ld l, a
+	ld a, [wRedrawFlashlightSrc1 + 1]
+	ld h, a
+	call _RedrawFlashlightColumn
+	ret
+
+RedrawFlashlightColumn3:: ; 1301 (0:1301)
+	ld a, [wRedrawFlashlightBlackDst1]
+	ld e, a
+	ld a, [wRedrawFlashlightBlackDst1 + 1]
+	ld d, a
+	call _RedrawFlashlightColumnBlack
+	xor a
+	ldh [hRedrawRowOrColumnMode], a ; end flashlight redraw
+	ret
+
+RedrawFlashlightRow0:: ; 1310 (0:1310)
+	ldh a, [hSCY]
+	and $07
+	ret nz        ; wait till we moved one complete tile in Y
+	ld a, [wRedrawFlashlightDst0]
+	ld e, a
+	ld a, [wRedrawFlashlightDst0 + 1]
+	ld d, a
+	ld a, [wRedrawFlashlightSrc0]
+	ld l, a
+	ld a, [wRedrawFlashlightSrc0 + 1]
+	ld h, a
+	call _RedrawFlashlightRow
+	ret
+
+RedrawFlashlightRow1:: ; 1329 (0:1329)
+	ld a, [wRedrawFlashlightBlackDst0]
+	ld e, a
+	ld a, [wRedrawFlashlightBlackDst0 + 1]
+	ld d, a
+	call _RedrawFlashlightRowBlack
+	ret
+; 0x12e8
+
+RedrawFlashlightRow2:: ; 1335 (0:1335)
+	ldh a, [hSCY]
+	and $0f
+	ret nz        ; wait till we moved two complete tiles in Y
+	ld a, [wRedrawFlashlightDst1]
+	ld e, a
+	ld a, [wRedrawFlashlightDst1 + 1]
+	ld d, a
+	ld a, [wRedrawFlashlightSrc1]
+	ld l, a
+	ld a, [wRedrawFlashlightSrc1 + 1]
+	ld h, a
+	call _RedrawFlashlightRow
+	ret
+
+RedrawFlashlightRow3:: ; 134e (0:134e)
+	ld a, [wRedrawFlashlightBlackDst1]
+	ld e, a
+	ld a, [wRedrawFlashlightBlackDst1 + 1]
+	ld d, a
+	call _RedrawFlashlightRowBlack
+	xor a
+	ldh [hRedrawRowOrColumnMode], a ; end flashlight redraw
+	ret
+
+_RedrawFlashlightColumn:: ; 135d (0:135d)
+	ld a, [wRedrawFlashlightWidthHeight]
+	add a
+	ld c, a
+.loop
+	ld a, [hli]
+	ld [de], a
+	ld a, SCREEN_WIDTH - 1
+	add l
+	ld l, a
+	jr nc, .noCarryScreen
+	inc h
+.noCarryScreen
+	ld a, BG_MAP_WIDTH
+	add e
+	ld e, a
+	jr nc, .noCarryBG
+	inc d
+.noCarryBG
+; the following 4 lines wrap us from bottom to top if necessary
+	ld a, d
+	and HIGH(vBGMap1 - vBGMap0 - $01)
+	or HIGH(vBGMap0)
+	ld d, a
+	dec c
+	jr nz, .loop
+	ldh a, [hRedrawRowOrColumnMode]
+	add $04                         ; inc by 4, because flashlight redraw
+	ldh [hRedrawRowOrColumnMode], a ; has four directions
+	ret
+
+_RedrawFlashlightRow:: ; 1382 (0:1382)
+	ld a, [wRedrawFlashlightWidthHeight]
+	ld c, a
+.loop
+	ld a, [hli]
+	ld [de], a
+	inc de
+	ld a, [hli]
+	ld [de], a
+	ld a, e
+	inc a
+; the following 6 lines wrap us from the right edge to the left edge if necessary
+	and BG_MAP_WIDTH - 1            ; mask lower address bits
+	ld b, a
+	ld a, e
+	and ($FF ^ (BG_MAP_WIDTH - 1))  ; mask upper address bits
+	or b
+	ld e, a
+	dec c
+	jr nz, .loop
+	ldh a, [hRedrawRowOrColumnMode]
+	add $04                         ; inc by 4, because flashlight redraw
+	ldh [hRedrawRowOrColumnMode], a ; has four directions
+	ret
+
+_RedrawFlashlightColumnBlack:: ; 139f (0:139f)
+	ld l, e
+	ld h, d
+	ld b, "■"
+	ld de, BG_MAP_WIDTH
+	ld a, [wRedrawFlashlightWidthHeight]
+	add a
+	ld c, a
+.loop
+	ld [hl], b
+	add hl, de
+; the following 4 lines wrap us from bottom to top if necessary
+	ld a, h
+	and HIGH(vBGMap1 - vBGMap0 - $01)
+	or HIGH(vBGMap0)
+	ld h, a
+	dec c
+	jr nz, .loop
+	ldh a, [hRedrawRowOrColumnMode]
+	add $04                         ; inc by 4, because flashlight redraw
+	ldh [hRedrawRowOrColumnMode], a ; has four directions
+	ret
+
+_RedrawFlashlightRowBlack:: ; 13bd (0:13bd)
+	ld l, e
+	ld h, d
+	ld b, "■"
+	ld a, [wRedrawFlashlightWidthHeight]
+	ld c, a
+.loop
+	ld [hl], b
+	inc hl
+	ld [hl], b
+	ld a, l
+	inc a
+; the following 6 lines wrap us from the right edge to the left edge if necessary
+	and BG_MAP_WIDTH - 1            ; mask lower address bits
+	ld d, a
+	ld a, l
+	and ($FF ^ (BG_MAP_WIDTH - 1))  ; mask upper address bits
+	or d
+	ld l, a
+	dec c
+	jr nz, .loop
+	ldh a, [hRedrawRowOrColumnMode]
+	add $04                         ; inc by 4, because flashlight redraw
+	ldh [hRedrawRowOrColumnMode], a ; has four directions
+	ret
+
+WaitForAutoBgMapTransfer:: ; 13dc (0:13dc)
+.loop
+	ldh a, [hBGMapMode]
+	and a
+	ret z
+	ldh a, [hBGMapTransferPosition]
+	and a
+	jr z, .done
+	call DelayFrame
+	jr .loop
+.done
+	xor a
+	ldh [hBGMapMode], a
+	ret
+
+; This function automatically transfers tile number data from the tile map at
+; wTileMap to VRAM during V-blank. Note that it only transfers one third of the
+; background per V-blank. It cycles through which third it draws.
+; This transfer is turned off when walking around the map, but is turned
+; on when talking to sprites, battling, using menus, etc. This is because
+; the above function, RedrawRowOrColumn, is used when walking to
+; improve efficiency.
+AutoBgMapTransfer:: ; 13ee (0:13ee)
+	ldh a, [hBGMapMode]
+	and a
+	ret z
+	ld [hSPTemp], sp
+	ldh a, [hBGMapTransferPosition]
+	and a
+	jr z, .transferTopThird
+	dec a
+	jr z, .transferMiddleThird
+.transferBottomThird
+	coord hl, 0, 12
+	ld sp, hl
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	ldh a, [hBGMapAddress]
+	ld l, a
+	ld de, 12 * BG_MAP_WIDTH
+	add hl, de
+	xor a
+	jr .doTransfer
+.transferTopThird
+	coord hl, 0, 0
+	ld sp, hl
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	ldh a, [hBGMapAddress]
+	ld l, a
+	ld a, $01
+	jr .doTransfer
+.transferMiddleThird
+	coord hl, 0, 6
+	ld sp, hl
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	ldh a, [hBGMapAddress]
+	ld l, a
+	ld de, 6 * BG_MAP_WIDTH
+	add hl, de
+	ld a, $02
+.doTransfer
+	ldh [hBGMapTransferPosition], a
+	ld a, $06                 ; 6 rows of SCREEN_WIDTH each
+	; fall through
+	
+TransferBgRows:: ; 1430 (0:1430)
+	ld bc, BG_MAP_WIDTH - SCREEN_WIDTH + 1
+.loop
+
+	rept SCREEN_WIDTH / 2 - 1 ; two bytes per pop minus last block
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	endr
+	
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	add hl, bc
+	dec a
+	jr nz, .loop
+	ldh a, [hSPTemp]
+	ld l, a
+	ldh a, [hSPTemp + 1]
+	ld h, a
+	ld sp, hl
+	ret
+
+; Copy [wVBCopyDoubleSize] 1bpp tiles
+; from wVBCopyDoubleSrc to wVBCopyDoubleDst.
+; wVBCopyDoubleDst must be aligned to 0x10 bytes.
+
+; While we're here, convert to 2bpp.
+; The process is straightforward:
+; copy each byte twice.
+VBlankCopyDouble:: ; 1470 (0:1470)
+	ld a, [wVBCopyDoubleSize]
+	and a
+	ret z
+	ld [hSPTemp], sp
+	ld hl, wVBCopyDoubleSrc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+	ld hl, wVBCopyDoubleDst
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [wVBCopyDoubleSize]
+	ld b, a
+	xor a
+	ld [wVBCopyDoubleSize], a
+.loop
+
+	rept 16/4 - 1 ; 16 bytes per 2bpp tile at 2 bytes per pop 
+	pop de        ; copied twice minus last block
+	ld [hl], e
+	inc l
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	ld [hl], d
+	inc l
+	endr
+	
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	ld [hl], d
+	inc hl
+	dec b
+	jr nz, .loop
+	ld a, l
+	ld [wVBCopyDoubleDst], a
+	ld a, h
+	ld [wVBCopyDoubleDst + 1], a
+	ld [wVBCopyDoubleSrc], sp
+	ldh a, [hSPTemp]
+	ld l, a
+	ldh a, [hSPTemp + 1]
+	ld h, a
+	ld sp, hl
+	ret
+
+; Copy 16 * [wVBCopySize] bytes
+; from wVBCopySrc to wVBCopyDst.
+; wVBCopyDst must be aligned to 0x10 bytes.
+
+; Source and destination addresses are updated,
+; so transfer can continue in subsequent calls.
+VBlankCopy:: ; 14c7 (0:14c7)
+	ld a, [wVBCopySize]
+	and a
+	ret z
+	ld [hSPTemp], sp
+	ld hl, wVBCopySrc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+	ld hl, wVBCopyDst
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [wVBCopySize]
+	ld b, a
+	xor a
+	ld [wVBCopySize], a
+.loop
+
+	rept 16/2 - 1 ; 16 bytes per transfer at 2 bytes per pop
+	pop de        ; minus last block
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	endr
+
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc hl
+	dec b
+	jr nz, .loop
+	ld a, l
+	ld [wVBCopyDst], a
+	ld a, h
+	ld [wVBCopyDst + 1], a
+	ld [wVBCopySrc], sp
+	ldh a, [hSPTemp]
+	ld l, a
+	ldh a, [hSPTemp + 1]
+	ld h, a
+	ld sp, hl
+	ret
+
+AnimateTileset:: ; 1522 (0:1522)
+	ldh a, [hROMBank]
+	push af
+	ld a, BANK(AnimateTilesetImpl)
+	call Bankswitch
+	call AnimateTilesetImpl
+	pop af
+	jp Bankswitch
+; 0x1531
+
+EnableSprites:: ; 1531 (0:1531)
+	nop
+	ld hl, rLCDC
+	set rLCDC_SPRITES_ENABLE, [hl]
+	ret
+; 0x1538
+
+Function_1538: ; 1538 (0:1538)
+	ld a, [$d14f]
+	bit 0, a
+	ret z
+	bit 7, a
+	ret nz
+	bit 2, a
+	res 2, a
+	ret z
+	ld [$d14f], a
+	ld [hSPTemp], sp
+	ld hl, $cbd2
+	ld sp, hl
+	ld hl, $9c20
+	ld a, $01
+	jp TransferBgRows
+
+; Copy 0x10 * [wVBCopyFarSize] bytes
+; from wVBCopyFarSrcBank::wVBCopyFarSrc to wVBCopyFarDst.
+; wVBCopyFarDst must be aligned to 0x10 bytes.
+
+; Source and destination addresses are updated,
+; so transfer can continue in subsequent calls.
+VBlankCopyFar:: ; 1558 (0:1558)
+	ld a, [wVBCopyFarSize]
+	and a
+	ret z
+	ld a, [wVBCopyFarSrcBank]
+	call Bankswitch
+	ld [hSPTemp], sp
+	ld hl, wVBCopyFarSrc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+	ld hl, wVBCopyFarDst
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [wVBCopyFarSize]
+	ld b, a
+	xor a
+	ld [wVBCopyFarSize], a
+.loop
+	rept 16/2 - 1 ; 16 bytes per transfer at 2 bytes per pop
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	endr
+	
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc hl
+	dec b
+	jr nz, .loop
+	ld [wVBCopyFarSrc], sp
+	ld sp, hl
+	ld [wVBCopyFarDst], sp
+	ldh a, [hSPTemp]
+	ld l, a
+	ldh a, [hSPTemp + 1]
+	ld h, a
+	ld sp, hl
+	ret
+; 0x15b5