6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2024-06-15 17:30:06 +00:00
Code Issues Projects Releases Wiki Activity

Use macpack for debugging, cosmetic changes

Browse Source 
git-svn-id: svn://svn.cc65.org/cc65/trunk@171 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2000-07-19 09:23:51 +00:00
parent 0b7aae0f07
commit bb4f3c4475
1 changed files with 28 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
libsrc/common/free.s
View File

@ -64,42 +64,46 @@
.import pushax, __hadd
.export _free
; Offsets into struct freeblock
.macpack generic
; Offsets into struct freeblock and other constant stuff
size = 0
next = 2
prev = 4
admin_space = 2
min_size = 6
size = 0
next = 2
prev = 4
; Code
_free: sta ptr1
stx ptr1+1 ; Save block
stx ptr1+1 ; Save block
; Is the argument NULL?
ora ptr1+1 ; Is the argument NULL?
beq @L9 ; Jump if yes
ora ptr1+1 ; Is the argument NULL?
beq @L9 ; Jump if yes
; Decrement the given pointer by 2. The size of the block is stored there.
; Decrement the given pointer by the admin space amount, so it points to the
; real block allocated. The size of the block is stored in the admin space.
; Remember the block size in ptr2.
sec
lda ptr1
sbc #2
sub #admin_space
sta ptr1
bcs @L1
dec ptr1+1
@L1: ldy #size+1
lda (ptr1),y ; High byte of size
sta ptr2+1 ; Save it
lda (ptr1),y ; High byte of size
sta ptr2+1 ; Save it
dey
lda (ptr1),y
sta ptr2
; Check if the block is on top of the heap
clc
adc ptr1
add ptr1
tay
lda ptr1+1
adc ptr2+1
@ -126,12 +130,11 @@ _free: sta ptr1
lda __hlast+1
sta ptr2+1 ; Pointer to last block now in ptr2
clc
ldy #size
lda (ptr2),y ; Low byte of block size
adc ptr2
add ptr2
tax
iny ; High byte of block size
iny ; High byte of block size
lda (ptr2),y
adc ptr2+1
@ -151,14 +154,14 @@ _free: sta ptr1
ldy #prev+1 ; Offset of ->prev field
lda (ptr2),y
sta ptr1+1 ; Remember f->prev in ptr1
sta ptr1+1 ; Remember f->prev in ptr1
sta __hlast+1
dey
lda (ptr2),y
sta ptr1 ; Remember f->prev in ptr1
sta ptr1 ; Remember f->prev in ptr1
sta __hlast
ora __hlast+1 ; -> prev == 0?
bne @L8 ; Jump if free list not empty
ora __hlast+1 ; -> prev == 0?
bne @L8 ; Jump if free list not empty
; Free list is now empty (A = 0)
@ -172,11 +175,11 @@ _free: sta ptr1
; Block before is now last block. ptr1 points to f->prev.
@L8: lda #$00
dey ; Points to high byte of ->next
dey ; Points to high byte of ->next
sta (ptr1),y
dey ; Low byte of f->prev->next
dey ; Low byte of f->prev->next
sta (ptr1),y
rts ; Done
rts ; Done
; The block is not on top of the heap. Add it to the free list.
@ -191,3 +194,4 @@ _free: sta ptr1