section .text,text
; 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
; Warning to developers: This function must only use PC-relative addressing as it is called from early boot before the kernel is properly mapped.
  public find_first_card
find_first_card:
  move.l #$ff0000, a0 ; a0 holds the address of the current card
ffc_loop:
  lea ($100,a0), a0 ; Move to the next card
  move.w ($fe,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 #$ff0000, a1 ; a0 holds the address of the current card
gac_loop:
  lea ($100,a1), a1 ; Move to the next card
  move.w ($fe,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 ($4,a0), a0 ; Move to the next buffer location
  subq.w #1, d0 ; Decement the count of available buffer locations
gac_next:
  cmpa.l #$ffff00, 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