m68k-backplane-computer/rom
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Finish RAM card sort

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This commit is contained in:
pjht 2023-11-02 18:29:11 -05:00
parent 6223392b9d
commit 5633e6154a
Signed by: pjht
GPG Key ID: CA239FC6934E6F3A
1 changed files with 24 additions and 10 deletions
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@ -5,12 +5,14 @@ _start:
bra.b find_first_card
romfindret:
move.l a0, a6 | Save the ROM card IO base in a6 for later
lea (0xF0, a6), a7 | Set up the stack at the end of the ROM's IO space RAM
move.l #0x8000, a1
bsr.w find_all_ram_cards
bsr.b find_largest_ram | Find the largest RAM card and put the IO base in a5
move.l #0x10000, a7 | Set up the stack at the end of the ROM card's RAM
bsr.w find_largest_ram | Find the largest RAM card and put the IO base in a5
move.l a0, a5
move.l d0, d7
move.l #0x8100, a1
bsr.w find_all_ram_cards
move.l #0x8100, a0
bsr.w sort_ram_cards
move.w #0x4, d0 | Find a storage card and put the IO base in a4
bsr.b find_first_card
move.l a0, a4
@ -81,6 +83,7 @@ fakestack:
| 1KB buffer in a1
| Returns list length in d0
| Clobbers a1, d1
find_all_ram_cards:
move.b #0, d0 | d0 holds the number of RAM cards found.
move.l #0xff0000, a0 | a0 holds the address of the current card.
@ -94,24 +97,35 @@ farc_loop:
addq.b #1, d0 | Increment the count of found RAM cards
bra.b farc_loop | Loop back and check the next card
farc_done:
move.l #0, (a1) | Write a null terminator on the end of the list
rts
| optimized bubble sort to sort RAM cards by size
| Buffer in a0
| Length in d0
| optimized bubble sort to sort RAM cards by size
| Clobbers d1, d2, d3, d4, a1, a2
sort_ram_cards:
move.b #0, d1 | d1 = newlen
move.b #1, d2 | d2 = i
move.l a0, a1 | a1 holds the pointer to the current pair
src_inner_loop:
| todo compare sizes
| PSEUDO: cmp snd, fst
cmp.b d0, d2 | if i >= length, exit the inner loop
bge.b src_inner_loop_done
move.l (a1), a2 | Read the first card's size
move.l (0x4, a2), d3
move.l (4, a1), a2 | Read the second card's size
move.l (0x4, a2), d4
cmp.l d3, d4 | if d4 <= d3, branch to src_pair_sorted
ble.b src_pair_sorted
| todo swap values
move.l (a1), d3 | Read the first value
move.l (0x4, a1), d4 | Read the second value
move.l d3, (0x4, a1) | Write the first value where the second value was
move.l d4, (a1)+ | Write the second value where the first value was and increment a1 for the next pair
move.b d2, d1 | i = newlem
src_pair_sorted:
addq.b #1, d2 | i++
cmp.b d0, d2 | if i < length, branch to inner loop
blt.b src_inner_loop
bra.b src_inner_loop
src_inner_loop_done:
move.b d1, d0 | len = newlen
cmp #1, d0 | if n > 1, branch to outer loop
bgt.b sort_ram_cards