ref: d7808d110f6b104a3e5ed7b21260ed8f1b718719
dir: /engine/items/inventory.asm/
; function to add an item (in varying quantities) to the player's bag or PC box ; INPUT: ; hl = address of inventory (either wNumBagItems or wNumBoxItems) ; [wcf91] = item ID ; [wItemQuantity] = item quantity ; sets carry flag if successful, unsets carry flag if unsuccessful AddItemToInventory_:: ld a, [wItemQuantity] ; a = item quantity push af push bc push de push hl push hl ld d, PC_ITEM_CAPACITY ; how many items the PC can hold ld a, LOW(wNumBagItems) cp l jr nz, .checkIfInventoryFull ld a, HIGH(wNumBagItems) cp h jr nz, .checkIfInventoryFull ; if the destination is the bag ld d, BAG_ITEM_CAPACITY ; how many items the bag can hold .checkIfInventoryFull ld a, [hl] sub d ld d, a ld a, [hli] and a jr z, .addNewItem .notAtEndOfInventory ld a, [hli] ld b, a ; b = ID of current item in table ld a, [wcf91] ; a = ID of item being added cp b ; does the current item in the table match the item being added? jp z, .increaseItemQuantity ; if so, increase the item's quantity inc hl ld a, [hl] cp $ff ; is it the end of the table? jr nz, .notAtEndOfInventory .addNewItem ; add an item not yet in the inventory pop hl ld a, d and a ; is there room for a new item slot? jr z, .done ; if there is room inc [hl] ; increment the number of items in the inventory ld a, [hl] ; the number of items will be the index of the new item add a dec a ld c, a ld b, 0 add hl, bc ; hl = address to store the item ld a, [wcf91] ld [hli], a ; store item ID ld a, [wItemQuantity] ld [hli], a ; store item quantity ld [hl], $ff ; store terminator jp .success .increaseItemQuantity ; increase the quantity of an item already in the inventory ld a, [wItemQuantity] ld b, a ; b = quantity to add ld a, [hl] ; a = existing item quantity add b ; a = new item quantity cp 100 jp c, .storeNewQuantity ; if the new quantity is less than 100, store it ; if the new quantity is greater than or equal to 100, ; try to max out the current slot and add the rest in a new slot sub 99 ld [wItemQuantity], a ; a = amount left over (to put in the new slot) ld a, d and a ; is there room for a new item slot? jr z, .increaseItemQuantityFailed ; if so, store 99 in the current slot and store the rest in a new slot ld a, 99 ld [hli], a jp .notAtEndOfInventory .increaseItemQuantityFailed pop hl and a jr .done .storeNewQuantity ld [hl], a pop hl .success scf .done pop hl pop de pop bc pop bc ld a, b ld [wItemQuantity], a ; restore the initial value from when the function was called ret ; function to remove an item (in varying quantities) from the player's bag or PC box ; INPUT: ; hl = address of inventory (either wNumBagItems or wNumBoxItems) ; [wWhichPokemon] = index (within the inventory) of the item to remove ; [wItemQuantity] = quantity to remove RemoveItemFromInventory_:: push hl inc hl ld a, [wWhichPokemon] ; index (within the inventory) of the item being removed sla a add l ld l, a jr nc, .noCarry inc h .noCarry inc hl ld a, [wItemQuantity] ; quantity being removed ld e, a ld a, [hl] ; a = current quantity sub e ld [hld], a ; store new quantity ld [wMaxItemQuantity], a and a jr nz, .skipMovingUpSlots ; if the remaining quantity is 0, ; remove the emptied item slot and move up all the following item slots .moveSlotsUp ld e, l ld d, h inc de inc de ; de = address of the slot following the emptied one .loop ; loop to move up the following slots ld a, [de] inc de ld [hli], a cp $ff jr nz, .loop ; update menu info xor a ld [wListScrollOffset], a ld [wCurrentMenuItem], a ld [wBagSavedMenuItem], a ld [wSavedListScrollOffset], a pop hl ld a, [hl] ; a = number of items in inventory dec a ; decrement the number of items ld [hl], a ; store new number of items ld [wListCount], a cp 2 jr c, .done ld [wMaxMenuItem], a jr .done .skipMovingUpSlots pop hl .done ret