blob: a156f6932da2b97f94426b92544496ecda361464 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
;;; see titlecompression.txt to understand how this works!
; cl65 -o comptitle.xex -t none comptitle.s
; comptitle.s.in is used by titlecomp.pl, to generate comptitle.s.
; __VARIABLE__ stuff is filled in by titlecomp.pl, q.v.
; DON'T bother to edit comptitle.s (edit the .in file instead)!
.include "atari.inc"
; size of uncompressed image, in bytes (but, needs to be
; a multiple of $100).
;imgsize = __SIZE__
imgsize = $1700
; these both need to be page-aligned. destination also needs
; to be aligned on a 4K boundary.
start = $8000
;start = $9000
;destination = $2400
srcptr = FR0
dstptr = FR0+2
pagecount = FR0+4
tmp = FR0+5
.word $ffff
.word start
.word end-1
.org start
compdata:
.incbin "comptitle.dat"
; table runs __FIRSTCODE__ to __LASTCODE__
table:
__TABLE__
; decompression code starts here
init:
lda #0
sta SDMCTL ; turn off the screen. newtitle.s turns it back on.
;;; for benchmarking only, remove!
;sta RTCLOK
;sta RTCLOK+1
;sta RTCLOK+2
lda #>imgsize
sta pagecount
lda #>compdata
sta srcptr+1
lda #>destination
sta dstptr+1
lda #0
sta srcptr
sta dstptr
tay
copyloop:
lda (srcptr),y
bpl storebyte ; 0-127 always represent themselves
cmp #__LASTCODE__+1
bcs storebyte ; anything above the last code represents itself
sta tmp
sec
sbc #__FIRSTCODE__
bcc notcode ; anything below the 1st code represents itself
tax
lda table,x
beq notcode
; got a zero-run code. A = number of bytes of zeroes to store.
storezerorun:
sty tmp
tay
dey
lda #0
tax
szloop:
sta (dstptr,x)
jsr incdest
beq done
nohi2:
dey
bpl szloop
ldy tmp
clc
bcc storedone
notcode:
lda tmp
storebyte:
sty tmp
ldy #0
sta (dstptr),y
jsr incdest
beq done
nohi:
ldy tmp
storedone:
iny
bne copyloop
inc srcptr+1
bne copyloop ; always branch (since srcptr never wraps around to 0)
done:
;;; for benchmarking only, remove!
;.byte $02 ; CIM, drops us to atari800 monitor
rts
incdest:
inc dstptr
bne iddone
inc dstptr+1
dec pagecount
iddone:
rts
end:
.word INITAD
.word INITAD+1
.word init
|
