2022-10-10 15:47:06 -05:00
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.global find_first_card
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2022-10-09 12:01:12 -05:00
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2022-10-10 15:47:06 -05:00
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| Finds the first card with the type in d0.b, and returns it's IO base address in a0, or 0 if not found
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| Clobbers d1
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find_first_card:
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move.l #0xff0000, a0 | a0 holds the address of the current card
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ffc_loop:
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2022-10-10 16:18:34 -05:00
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lea (0x100, a0), a0 | Move to the next card
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2022-10-10 15:47:06 -05:00
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move.b (0xff, a0), d1 | Load the type of the card into d1
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beq.b ffc_done | If the type is 0 (empty slot), we have scanned all cards, so exit the loop
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cmp.b d0, d1 | If the card is the type we want, return with the address in a0
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beq.b ffc_done
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bra.b ffc_loop | Loop back and check the next card
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ffc_done:
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rts
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2022-10-10 16:18:34 -05:00
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get_all_cards:
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| Gets the indexes of the cards with the specified type
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| a0 is a pointer to the buffer to store the results in
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| d0 is the length of the buffer in 4 byte units
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| d1 is the type of card to find
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move.l #0xff0000, a1 | a0 holds the address of the current card
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gac_loop:
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lea (0x100, a1), a1 | Move to the next card
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move.b (0xff, a1), d2 | Load the type of the card into d1
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cmp.b d1, d2 | Check whether the type of the current card is the type we want
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bne.b gac_next | Skip the card if it is not
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move.l a1, (a0) | Put the card base into the buffer
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lea (0x4, a0), a0 | Move to the next buffer location
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subq.w #1, d0 | Decement the count of available buffer locations
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gac_next:
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cmpa.l #0xffff00, a1 | Check if we have gone through all the cards
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beq.b gac_done | If so, return
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cmpi.b #0, d0 | Check if we have filled the buffer
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beq.b gac_done | If so, returm
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bra.b gac_loop
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gac_done:
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rts
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