Organize the engine/ directory, take 2

Renamed `game` to `games` and `menu` to `menus`.
Moved some functions from `engine/routines/` to their fitting subdirectories.

Made two new subdirectories:
* engine/rtc: Contains all RTC-related things. Menus, hardware, misc
functions.
* engine/items: Contains all item-related things. Pack, item effects,
other item handlers.

engine/items/switch_items.asm

@@ -0,0 +1,274 @@
+SwitchItemsInBag: ; 2490c (9:490c)
+	ld a, [wSwitchItem]
+	and a
+	jr z, .init
+	ld b, a
+	ld a, [wScrollingMenuCursorPosition]
+	inc a
+	cp b
+	jr z, .trivial
+	ld a, [wScrollingMenuCursorPosition]
+	call ItemSwitch_GetNthItem
+	ld a, [hl]
+	cp -1
+	ret z
+	ld a, [wSwitchItem]
+	dec a
+	ld [wSwitchItem], a
+	call Function249a7
+	jp c, Function249d1
+	ld a, [wScrollingMenuCursorPosition]
+	ld c, a
+	ld a, [wSwitchItem]
+	cp c
+	jr c, .asm_2497a
+	jr .asm_2494a
+
+.init
+	ld a, [wScrollingMenuCursorPosition]
+	inc a
+	ld [wSwitchItem], a
+	ret
+
+.trivial
+	xor a
+	ld [wSwitchItem], a
+	ret
+
+.asm_2494a
+	ld a, [wSwitchItem]
+	call Function24a40
+	ld a, [wScrollingMenuCursorPosition]
+	ld d, a
+	ld a, [wSwitchItem]
+	ld e, a
+	call Function24a6c
+	push bc
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	dec hl
+	push hl
+	call ItemSwitch_ConvertSpacingToDW
+	add hl, bc
+	ld d, h
+	ld e, l
+	pop hl
+	pop bc
+	call Function24aab
+	ld a, [wScrollingMenuCursorPosition]
+	call Function24a4d
+	xor a
+	ld [wSwitchItem], a
+	ret
+
+.asm_2497a
+	ld a, [wSwitchItem]
+	call Function24a40
+	ld a, [wScrollingMenuCursorPosition]
+	ld d, a
+	ld a, [wSwitchItem]
+	ld e, a
+	call Function24a6c
+	push bc
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	ld d, h
+	ld e, l
+	call ItemSwitch_ConvertSpacingToDW
+	add hl, bc
+	pop bc
+	call CopyBytes
+	ld a, [wScrollingMenuCursorPosition]
+	call Function24a4d
+	xor a
+	ld [wSwitchItem], a
+	ret
+
+Function249a7: ; 249a7 (9:49a7)
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	ld d, h
+	ld e, l
+	ld a, [wScrollingMenuCursorPosition]
+	call ItemSwitch_GetNthItem
+	ld a, [de]
+	cp [hl]
+	jr nz, .asm_249cd
+	ld a, [wScrollingMenuCursorPosition]
+	call Function24a97
+	cp 99
+	jr z, .asm_249cd
+	ld a, [wSwitchItem]
+	call Function24a97
+	cp 99
+	jr nz, .asm_249cf
+.asm_249cd
+	and a
+	ret
+
+.asm_249cf
+	scf
+	ret
+
+Function249d1: ; 249d1 (9:49d1)
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	inc hl
+	push hl
+	ld a, [wScrollingMenuCursorPosition]
+	call ItemSwitch_GetNthItem
+	inc hl
+	ld a, [hl]
+	pop hl
+	add [hl]
+	cp 100
+	jr c, .asm_24a01
+	sub 99
+	push af
+	ld a, [wScrollingMenuCursorPosition]
+	call ItemSwitch_GetNthItem
+	inc hl
+	ld [hl], 99
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	inc hl
+	pop af
+	ld [hl], a
+	xor a
+	ld [wSwitchItem], a
+	ret
+
+.asm_24a01
+	push af
+	ld a, [wScrollingMenuCursorPosition]
+	call ItemSwitch_GetNthItem
+	inc hl
+	pop af
+	ld [hl], a
+	ld hl, wMenuData_ItemsPointerAddr
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [wSwitchItem]
+	cp [hl]
+	jr nz, .asm_24a25
+	dec [hl]
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	ld [hl], $ff
+	xor a
+	ld [wSwitchItem], a
+	ret
+
+.asm_24a25
+	dec [hl]
+	call ItemSwitch_ConvertSpacingToDW
+	push bc
+	ld a, [wSwitchItem]
+	call ItemSwitch_GetNthItem
+	pop bc
+	push hl
+	add hl, bc
+	pop de
+.asm_24a34
+	ld a, [hli]
+	ld [de], a
+	inc de
+	cp $ff
+	jr nz, .asm_24a34
+	xor a
+	ld [wSwitchItem], a
+	ret
+
+Function24a40: ; 24a40 (9:4a40)
+	call ItemSwitch_GetNthItem
+	ld de, wd002
+	call ItemSwitch_ConvertSpacingToDW
+	call CopyBytes
+	ret
+
+Function24a4d: ; 24a4d (9:4a4d)
+	call ItemSwitch_GetNthItem
+	ld d, h
+	ld e, l
+	ld hl, wd002
+	call ItemSwitch_ConvertSpacingToDW
+	call CopyBytes
+	ret
+
+ItemSwitch_GetNthItem: ; 24a5c (9:4a5c)
+	push af
+	call ItemSwitch_ConvertSpacingToDW
+	ld hl, wMenuData_ItemsPointerAddr
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	inc hl
+	pop af
+	call AddNTimes
+	ret
+
+Function24a6c: ; 24a6c (9:4a6c)
+	push hl
+	call ItemSwitch_ConvertSpacingToDW
+	ld a, d
+	sub e
+	jr nc, .dont_negate
+	dec a
+	cpl
+.dont_negate
+	ld hl, 0
+	call AddNTimes
+	ld b, h
+	ld c, l
+	pop hl
+	ret
+
+ItemSwitch_ConvertSpacingToDW: ; 24a80 (9:4a80)
+; This function is absolutely idiotic.
+	push hl
+	ld a, [wMenuData_ScrollingMenuSpacing]
+	ld c, a
+	ld b, 0
+	ld hl, .spacing_dws
+	add hl, bc
+	add hl, bc
+	ld c, [hl]
+	inc hl
+	ld b, [hl]
+	pop hl
+	ret
+
+; 24a91 (9:4a91)
+
+.spacing_dws ; 24a91
+	dw 0, 1, 2
+; 24a97
+
+Function24a97: ; 24a97 (9:4a97)
+	push af
+	call ItemSwitch_ConvertSpacingToDW
+	ld a, c
+	cp 2
+	jr nz, .not_2
+	pop af
+	call ItemSwitch_GetNthItem
+	inc hl
+	ld a, [hl]
+	ret
+
+.not_2
+	pop af
+	ld a, $1
+	ret
+
+Function24aab: ; 24aab (9:4aab)
+.loop
+	ld a, [hld]
+	ld [de], a
+	dec de
+	dec bc
+	ld a, b
+	or c
+	jr nz, .loop
+	ret