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Clean up comments and add get_all_cards

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This commit is contained in:
pjht 2022-10-10 16:18:34 -05:00
parent 11084131f6
commit 57b18a0ba4
2 changed files with 25 additions and 2 deletions
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2
boot/boot.68k
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@ -62,7 +62,7 @@ jmp (a0) | Jump to the entry point of the program
find_first_card:
move.l #0xff0000, a0 | a0 holds the address of the current card
ffc_loop:
lea (0x100, a0), a0 | adda.l #$100, a0 | Move to the next card
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

25
kernel/cards.68k
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@ -5,7 +5,7 @@
find_first_card:
move.l #0xff0000, a0 | a0 holds the address of the current card
ffc_loop:
lea (0x100, a0), a0 | adda.l #$100, a0 | Move to the next card
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
@ -13,3 +13,26 @@ ffc_loop:
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