LoadCardDataAsync: ; to be called as async
  ei
  ld a, 1 
  ldh [vBlocked], a
  ldh a, [vSelectedCardIndex]
  ldh [vPreviousCardIndex], a

  ld b, 0
  ld c, a ; load bc from a, the number of the card in the cards list
  ld hl, Cards + 1 ; skip the length prefix
  add hl, bc
  add hl, bc
  add hl, bc ; triple add bc entries are bank, addr, addr
  
  ld a, [hl+]
  ld [rROMB0], a ; select the specified bank
  ; follow the pointer we're looking at
  ld a, [hl+]
  ld c, a
  ld a, [hl+]
  ld b, a

  ld h, b
  ld l, c ; hl now contains the address of the card data.

  ld a, LOW(.duringDraw)
  ld [vAsyncNext], a 
  ld a, HIGH(.duringDraw)
  ld [vAsyncNext+1], a 
  ld a, 0
  ld [vAsyncAfter], a
  ld [vAsyncAfter+1], a
  di
  nop
  nop
  ret
.duringDraw
  di ; these function calls should be fast so we'll disable interrupts and do them
  nop
  ; synchronously
  
  ; hl points to a card struct.
  ; card struct starts with a sequence of length-prefixed strings in memory
  ; so when we're done writing one, hl will be correctly placed to read the next
  ; length-prefixed print doesn't require passing a length
  ; so all we have to set is the destination for each
  ld de, $9800 + 32*11 + 10
  call PrintString
  ld de, $9800 + 32*12 + 10
  call PrintString
  ld de, $9800 + 32*14 + 10
  call PrintString
  ld de, $9800 + 32*15 + 10
  call PrintString
  ld de, $9800 + 32*16 + 10
  call PrintString
  
  ei

  ; hl now contains the address after all the strings.
  ; [hl+] and [hl+] read the length first, into bc
  ld a, [hl+]
  ld c, a
  ld a, [hl+]
  ld b, a ; bc has length
  ld a, [hl+]
  ld e, a
  ld a, [hl+]
  ld d, a ; de has source of tile range copy
  
  ld h, d 
  ld l, e  ; source
  ld de, $9800 + 32 + 1 ; destination
  ld b, 16 ; height
  ld c, 8 ; width
  
  ld a, LOW(CopyTilesToMapThreadsafe)
  ld [vAsyncNext], a 
  ld a, HIGH(CopyTilesToMapThreadsafe)
  ld [vAsyncNext+1], a 
  ld a, LOW(.afterCopyTiles)
  ld [vAsyncAfter], a
  ld a, HIGH(.afterCopyTiles)
  ld [vAsyncAfter+1], a
  di
  nop
  nop
  ret
.afterCopyTiles
  ei
  ldh a, [vSelectedCardIndex]
  ldh [vPreviousCardIndex], a

  ld b, 0
  ld c, a ; load bc from a, the number of the card in the cards list
  ld hl, Cards + 1 ; skip the length prefix
  add hl, bc
  add hl, bc
  add hl, bc ; triple add bc entries are bank, addr, addr
  
  ld a, [hl+]
  ld [rROMB0], a ; select the specified bank
  ; follow the pointer we're looking at
  ld a, [hl+]
  ld c, a
  ld a, [hl+]
  ld b, a

  ld h, b
  ld l, c ; hl now contains the address of the card data.
  di
  call PassList
  call PassList
  call PassList
  call PassList
  call PassList ; skip the strings
  ei
  inc hl 
  inc hl ; skip tile map width
  inc hl 
  inc hl ; skip tile map pointer
  ld a, [hl+]
  ld c, a
  ld a, [hl+]
  ld b, a ; bc has length of tile data
  ld a, [hl+]
  ld e, a
  ld a, [hl+]
  ld d, a ; de has source of tile range copy

  ld h, d
  ld l, e ; hl takes the source

  ld de, $9000 + VARIABLE_TILES_START*$10 ; always load tile data into the same spot in vram
  ld a, LOW(CopyRangeUnsafe)
  ld [vAsyncNext], a 
  ld a, HIGH(CopyRangeUnsafe)
  ld [vAsyncNext+1], a 
  ld a, LOW(.afterLoadingTiles)
  ld [vAsyncAfter], a
  ld a, HIGH(.afterLoadingTiles)
  ld [vAsyncAfter+1], a  
  di
  nop
  nop
  ret
.afterLoadingTiles
  ei
  ld a, 0 
  ldh [vBlocked], a 
  
  ld a, 0
  ld [vAsyncNext], a 
  ld [vAsyncNext+1], a 
  ld [vAsyncAfter], a
  ld [vAsyncAfter+1], a  
  di
  nop
  nop
  
  ret