.global find_first_card

| Finds the first card with the type in d0.b, and returns it's IO base address in a0, or 0 if not found
| Clobbers d1
find_first_card:
  move.l #0xff0000, a0 | a0 holds the address of the current card
ffc_loop:
  lea (0x100, a0), a0 | Move to the next card
  move.b (0xff, a0), d1 | Load the type of the card into d1
  beq.b ffc_done | If the type is 0 (empty slot), we have scanned all cards, so exit the loop
  cmp.b d0, d1 | If the card is the type we want, return with the address in a0
  beq.b ffc_done
  bra.b ffc_loop | Loop back and check the next card
ffc_done:
  rts

get_all_cards:
| Gets the indexes of the cards with the specified type
| a0 is a pointer to the buffer to store the results in
| d0 is the length of the buffer in 4 byte units
| d1 is the type of card to find
  move.l #0xff0000, a1 | a0 holds the address of the current card
gac_loop:
  lea (0x100, a1), a1 | Move to the next card
  move.b (0xff, a1), d2 | Load the type of the card into d1
  cmp.b d1, d2 | Check whether the type of the current card is the type we want 
  bne.b gac_next | Skip the card if it is not
  move.l a1, (a0) | Put the card base into the buffer
  lea (0x4, a0), a0 | Move to the next buffer location
  subq.w #1, d0 | Decement the count of available buffer locations
gac_next:
  cmpa.l #0xffff00, a1 | Check if we have gone through all the cards
  beq.b gac_done | If so, return
  cmpi.b #0, d0 | Check if we have filled the buffer
  beq.b gac_done | If so, returm
  bra.b gac_loop
gac_done:
  rts