diff options
Diffstat (limited to 'programs/sub-suite/tmp-stuff/free-new.s')
| -rw-r--r-- | programs/sub-suite/tmp-stuff/free-new.s | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/programs/sub-suite/tmp-stuff/free-new.s b/programs/sub-suite/tmp-stuff/free-new.s new file mode 100644 index 0000000..dad19d0 --- /dev/null +++ b/programs/sub-suite/tmp-stuff/free-new.s @@ -0,0 +1,143 @@ +.include "declare.s" + +.org 0 + +; free: Free allocated memory. +; Input: D = Pointer to allocated memory. +; Output: none. +; Caller preserved registers: D. +; Callie preserved registers: A, B, X, Y, E. + +free: + pha.q ; Preserve A. + phb.q ; Preserve B. + phx.q ; Preserve X. + phy.q ; Preserve Y. + phe.q ; Preserve E. + and #0 ; Reset A. + tab ; Reset B. + tax ; Reset X. + tay ; Reset Y. + mov a, d ; Get the passed pointer. + bne @getrealblk ; The pointer isn't NULL, so get the real block. + bra @end ; The pointer is NULL, so we're done. +@getrealblk: + sub #8 ; Get the start of the used block. + mov.q a, (a) ; Get the start of the real block. + mov.q b, (a+ublk.size) ; Get the size of the real block. + lea e, (a+b) ; Add the size of the real block with the start of the real block. + cmp.q e, heapptr ; Is this block on top of the heap? + bne @heapadd ; No, so add it to the free block list. +@dectop: + mov.q heapptr, (a) ; Set the top of the heap to the start of the previous real block. +@chklastblk: + mov.q b, heapl ; Get the last free list entry. + beq @end ; The free list is empty, so we're done. + ldy #fblk.size ; Get the size of the block. + mov.q a, (b+fblk.size) ; Get the size of the block. + lea e, (a+b) ; Add the size of the block, with the address of the block entry. + cmp.q e, heapptr ; Is the last block on top of the heap? + bne @end ; No, so we're done. +@delblk: + mov.q heapptr, b ; Yes, so remove the last block. +@correctblk: + mov.q a, (b+fblk.prev) ; Get the previous block. + sta.q heapl ; Set the last block to the previous block. + bne @delnxtblk ; The previous block isn't NULL, so delete the next block. + sta.q heapf ; The previous block is NULL, so empty the free list. + bra @end ; We are done. +@delnxtblk: + lea e, (a+fblk.next) ; Delete the next block. + stz.q (e) ; +@end: + ple.q ; Restore E. + ply.q ; Restore Y. + plx.q ; Restore X. + plb.q ; Restore B. + pla.q ; Restore A. + rts ; End of free. + + +@heapadd: + mov.q y, heapf ; Get the first block. + bne @srchflst ; The Free list isn't empty, so start searching the free list. +@empty: + mov.q (a+fblk.next), y ; Clear the next block. + mov.q (a+fblk.prev), y ; Clear the previous block. + sta.q heapf ; Set the first block entry to the current block. + sta.q heapl ; Set the last block entry to the current block. + bra @end ; We are done. +@srchflst: +@loop: + cmp y, a ; Is the right pointer at, or below the current block? + beq @nextright ; Yes, so get the next right pointer. + bcs @chkrmerge ; No, so do the right block merge. +@nextright: + tyx ; Set the left pointer, to the right pointer. + mov.q y, (y+fblk.next) ; Set the current right pointer to the next right pointer. + bne @loop ; The next right pointer isn't NULL, so keep looping. +@st_lmerge2: + mov.q (a+fblk.next), y ; Clear the next block. + sta.q heapl ; Set the last free block entry to it. + bra @chklmerge2 ; Do the left block merge. +@chkrmerge: + lea e, (a+b) ; Add the size of the current block, to the current block. + cmp e, y ; Is the current block the same as the right block? + bne @normerge ; No, so don't merge the right block. +@rmerge: + mov e, b ; Get the size of the current block. + add.q e, (y+fblk.size) ; Add the size of the current block, with the size of the right pointer. + mov.q (a+fblk.size), e ; Set the size of the current block, to the new size. +@rmerge2: + lea fblk.next ; Get the next right pointer. + mov.q (a+e), (y+e) ; Set the next block, to the next right pointer. + mov.q b, (y+e) ; Save the next block. + beq @setheapl ; The next block is NULL, so set the last block. +@setprev: + mov.q (b+fblk.prev), a ; Set the previous block to the current block. + bra @chklmerge ; Do the left block merge. +@setheapl: + sta.q heapl ; Set the last block to the current block. + bra @chklmerge ; Do the left block merge. +@normerge: + mov.q (a+fblk.next), y ; Set the next block to the right pointer. + mov.q (y+fblk.prev), a ; Set the previous right pointer to the current block. +@chklmerge: + and x, x ; Is the left pointer NULL? + bne @chklmerge2 ; No, so keep checking. +@newstart: + mov.q (a+fblk.prev), x ; + sta.q heapf ; Set the first block, to the current block. + bra @end2 ; We are done. +@chklmerge2: + mov.q e, (x+fblk.size) ; Get the size of the left block. + add e, x ; Add the size of the left block, to the left pointer. + cmp e, a ; Is the left block adjacent? + bne @nolmerge ; No, so don't merge the left block. +@lmerge: + lea fblk.size ; Set the offset to the block size. + add.q (x+e), (a+e) ; Add the size of the left block, with the size of the current block. +@lmerge2: + lea fblk.next ; Set the offset to the next block. + mov.q (x+e), (a+e) ; Set the next left pointer, to the next block. + mov.q b, (a+e) ; Get the next block. + beq @newlast ; The next block is NULL, so set the last block. +@lprev: + mov.q (b+fblk.prev), x ; Set the next left pointer's previous pointer to the left pointer. + bra @end2 ; We are done. +@newlast: + stx.q heapl ; Set the last block, to the left pointer. + bra @end2 ; We are done. +@nolmerge: + mov.q (x+fblk.next), a ; Set the next left pointer, to the current block. +@nolmerge2: + mov.q (a+fblk.prev), x ; Set the previous block, to the left pointer. +@end2: + ple.q ; Restore E. + ply.q ; Restore Y. + plb.q ; Restore B. + pla.q ; Restore A. + rts ; End of free. + +a +q |