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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
#undef DEBUG
.text
.extern _savegpr_21
.extern _restgpr_21
.extern OSReport
.set data, 31
.set inp_top, 30
.set outp, 29
.set inp, 28
.set outp_save, 27
.set flag, 26
.set count8, 25
.set index, 24
.set len, 23
.set t_temp, 22
.set sp, 1
.global UncompressBackward
UncompressBackward:
stwu sp, -0x40(sp)
mflr r0
stw r0, 0x44(sp)
addi r11, sp, 0x40
bl _savegpr_21
cmpwi r3, 0
beq exit
# endianness issues are annoying.
li r9, -4
lwbrx outp, r3, r9
li r9, -8
lwbrx inp_top, r3, r9
#lbz r6, -4(r3)
#lbz r7, -3(r3)
#lbz r8, -2(r3)
#lbz r9, -1(r3)
#slwi r9, r9, 24
#slwi r8, r8, 16
#slwi r7, r6, 8
#or r9, r9, r8
#or r9, r9, r7
#or inp_top, r9, r6
#lbz r6, -8(r3)
#lbz r7, -7(r3)
#lbz r8, -6(r3)
#lbz r9, -5(r3)
#slwi r9, r9, 24
#slwi r8, r8, 16
#slwi r7, r6, 8
#or r9, r9, r8
#or r9, r9, r7
#or outp, r9, r6
add outp, r3, outp
srwi t_temp, inp_top, 24
sub inp, r3, t_temp
clrlwi inp_top, inp_top, 8
sub inp_top, r3, inp_top
mr outp_save, outp
#ifdef DEBUG
crclr 4*cr0+eq
lis r3, Start@h
ori r3, r3, Start@l
mr r4, outp
mr r5, inp
bl OSReport
#endif
loop:
cmpw inp, inp_top
ble end_loop
lbzu flag, -1(inp)
#ifdef DEBUG
crclr 4*cr0+eq
lis r3, MFlag@h
ori r3, r3, MFlag@l
mr r4, outp
mr r5, inp
mr r6, flag
bl OSReport
#endif
li count8, 8
loop8:
subi count8, count8, 1
cmpwi count8, 0
blt loop
andi. r12, flag, 0x80
bne blockcopy
bytecopy:
#ifdef DEBUG
crclr 4*cr0+eq
lis r3, MOne@h
ori r3, r3, MOne@l
mr r4, outp
mr r5, inp
lbz r6, -1(inp)
lbz r7, -1(inp)
bl OSReport
#endif
lbzu data, -1(inp)
stbu data, -1(outp)
b joinhere
blockcopy:
lbz len, -1(inp)
lbz index, -2(inp)
slwi t_temp, len, 8
or index, index, t_temp
clrlwi index, index, 20
addi index, index, 2
srwi len, len, 4
addi len, len, 2
#ifdef DEBUG
crclr 4*cr0+eq
lis r3, MTwo@h
ori r3, r3, MTwo@l
mr r4, outp
mr r5, inp
mr r6, len
mr r7, index
bl OSReport
#endif
subi inp, inp, 2
patterncopy:
lbzx data, outp, index
stbu data, -1(outp)
subi len, len, 1
cmpwi len, 0
bge patterncopy
joinhere:
cmpw inp, inp_top
slwi flag, flag, 1
bgt loop8
end_loop:
exit:
#ifdef DEBUG
crclr 4*cr0+eq
lis r3, Done@h
ori r3, r3, Done@l
mr r4, outp
mr r5, inp
bl OSReport
#endif
addi r11, sp, 0x40
bl _restgpr_21
lwz r0, 0x44(sp)
mtlr r0
addi sp, sp, 0x40
blr
.data
Start: .string "[O=%p I=%p] START\n"
MFlag: .string "[O=%p I=%p] Flag: %02x\n"
MOne: .string "[O=%p I=%p] Copy: %02x [%c]\n"
MTwo: .string "[O=%p I=%p] Copy: %02x bytes from offset %06x\n"
Done: .string "[O=%p I=%p] END\n"
.align 4
|
