|
@@ -1,184 +0,0 @@
|
1
|
|
-/*
|
2
|
|
- * Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
|
3
|
|
- *
|
4
|
|
- * This file is free software; you can redistribute it and/or
|
5
|
|
- * modify it under the terms of the GNU General Public License as
|
6
|
|
- * published by the Free Software Foundation; either version 2 of
|
7
|
|
- * the License, or (at your option) any later version.
|
8
|
|
- *
|
9
|
|
- * Originally this code was part of ucl the data compression library
|
10
|
|
- * for upx the ``Ultimate Packer of eXecutables''.
|
11
|
|
- *
|
12
|
|
- * - Converted to gas assembly, and refitted to work with etherboot.
|
13
|
|
- * Eric Biederman 20 Aug 2002
|
14
|
|
- *
|
15
|
|
- * - Structure modified to be a subroutine call rather than an
|
16
|
|
- * executable prefix.
|
17
|
|
- * Michael Brown 30 Mar 2004
|
18
|
|
- *
|
19
|
|
- * - Modified to be compilable as either 16-bit or 32-bit code.
|
20
|
|
- * Michael Brown 9 Mar 2005
|
21
|
|
- */
|
22
|
|
-
|
23
|
|
-FILE_LICENCE ( GPL2_OR_LATER )
|
24
|
|
-
|
25
|
|
-/****************************************************************************
|
26
|
|
- * This file provides the decompress() and decompress16() functions
|
27
|
|
- * which can be called in order to decompress an image compressed with
|
28
|
|
- * the nrv2b utility in src/util.
|
29
|
|
- *
|
30
|
|
- * These functions are designed to be called by the prefix. They are
|
31
|
|
- * position-independent code.
|
32
|
|
- *
|
33
|
|
- * The same basic assembly code is used to compile both
|
34
|
|
- * decompress() and decompress16().
|
35
|
|
- ****************************************************************************
|
36
|
|
- */
|
37
|
|
-
|
38
|
|
- .text
|
39
|
|
- .arch i386
|
40
|
|
- .section ".prefix.lib", "ax", @progbits
|
41
|
|
-
|
42
|
|
-#ifdef CODE16
|
43
|
|
-/****************************************************************************
|
44
|
|
- * decompress16 (real-mode near call, position independent)
|
45
|
|
- *
|
46
|
|
- * Decompress data in 16-bit mode
|
47
|
|
- *
|
48
|
|
- * Parameters (passed via registers):
|
49
|
|
- * %ds:%esi - Start of compressed input data
|
50
|
|
- * %es:%edi - Start of output buffer
|
51
|
|
- * Returns:
|
52
|
|
- * %ds:%esi - End of compressed input data
|
53
|
|
- * %es:%edi - End of decompressed output data
|
54
|
|
- * All other registers are preserved
|
55
|
|
- *
|
56
|
|
- * NOTE: It would be possible to build a smaller version of the
|
57
|
|
- * decompression code for -DKEEP_IT_REAL by using
|
58
|
|
- * #define REG(x) x
|
59
|
|
- * to use 16-bit registers where possible. This would impose limits
|
60
|
|
- * that the compressed data size must be in the range [1,65533-%si]
|
61
|
|
- * and the uncompressed data size must be in the range [1,65536-%di]
|
62
|
|
- * (where %si and %di are the input values for those registers). Note
|
63
|
|
- * particularly that the lower limit is 1, not 0, and that the upper
|
64
|
|
- * limit on the input (compressed) data really is 65533, since the
|
65
|
|
- * algorithm may read up to three bytes beyond the end of the input
|
66
|
|
- * data, since it reads dwords.
|
67
|
|
- ****************************************************************************
|
68
|
|
- */
|
69
|
|
-
|
70
|
|
-#define REG(x) e ## x
|
71
|
|
-#define ADDR32 addr32
|
72
|
|
-
|
73
|
|
- .code16
|
74
|
|
- .globl decompress16
|
75
|
|
-decompress16:
|
76
|
|
-
|
77
|
|
-#else /* CODE16 */
|
78
|
|
-
|
79
|
|
-/****************************************************************************
|
80
|
|
- * decompress (32-bit protected-mode near call, position independent)
|
81
|
|
- *
|
82
|
|
- * Parameters (passed via registers):
|
83
|
|
- * %ds:%esi - Start of compressed input data
|
84
|
|
- * %es:%edi - Start of output buffer
|
85
|
|
- * Returns:
|
86
|
|
- * %ds:%esi - End of compressed input data
|
87
|
|
- * %es:%edi - End of decompressed output data
|
88
|
|
- * All other registers are preserved
|
89
|
|
- ****************************************************************************
|
90
|
|
- */
|
91
|
|
-
|
92
|
|
-#define REG(x) e ## x
|
93
|
|
-#define ADDR32
|
94
|
|
-
|
95
|
|
- .code32
|
96
|
|
- .globl decompress
|
97
|
|
-decompress:
|
98
|
|
-
|
99
|
|
-#endif /* CODE16 */
|
100
|
|
-
|
101
|
|
-#define xAX REG(ax)
|
102
|
|
-#define xCX REG(cx)
|
103
|
|
-#define xBP REG(bp)
|
104
|
|
-#define xSI REG(si)
|
105
|
|
-#define xDI REG(di)
|
106
|
|
-
|
107
|
|
- /* Save registers */
|
108
|
|
- push %xAX
|
109
|
|
- pushl %ebx
|
110
|
|
- push %xCX
|
111
|
|
- push %xBP
|
112
|
|
- /* Do the decompression */
|
113
|
|
- cld
|
114
|
|
- xor %xBP, %xBP
|
115
|
|
- dec %xBP /* last_m_off = -1 */
|
116
|
|
- jmp dcl1_n2b
|
117
|
|
-
|
118
|
|
-decompr_literals_n2b:
|
119
|
|
- ADDR32 movsb
|
120
|
|
-decompr_loop_n2b:
|
121
|
|
- addl %ebx, %ebx
|
122
|
|
- jnz dcl2_n2b
|
123
|
|
-dcl1_n2b:
|
124
|
|
- call getbit32
|
125
|
|
-dcl2_n2b:
|
126
|
|
- jc decompr_literals_n2b
|
127
|
|
- xor %xAX, %xAX
|
128
|
|
- inc %xAX /* m_off = 1 */
|
129
|
|
-loop1_n2b:
|
130
|
|
- call getbit1
|
131
|
|
- adc %xAX, %xAX /* m_off = m_off*2 + getbit() */
|
132
|
|
- call getbit1
|
133
|
|
- jnc loop1_n2b /* while(!getbit()) */
|
134
|
|
- sub $3, %xAX
|
135
|
|
- jb decompr_ebpeax_n2b /* if (m_off == 2) goto decompr_ebpeax_n2b ? */
|
136
|
|
- shl $8, %xAX
|
137
|
|
- ADDR32 movb (%xSI), %al /* m_off = (m_off - 3)*256 + src[ilen++] */
|
138
|
|
- inc %xSI
|
139
|
|
- xor $-1, %xAX
|
140
|
|
- jz decompr_end_n2b /* if (m_off == 0xffffffff) goto decomp_end_n2b */
|
141
|
|
- mov %xAX, %xBP /* last_m_off = m_off ?*/
|
142
|
|
-decompr_ebpeax_n2b:
|
143
|
|
- xor %xCX, %xCX
|
144
|
|
- call getbit1
|
145
|
|
- adc %xCX, %xCX /* m_len = getbit() */
|
146
|
|
- call getbit1
|
147
|
|
- adc %xCX, %xCX /* m_len = m_len*2 + getbit()) */
|
148
|
|
- jnz decompr_got_mlen_n2b /* if (m_len == 0) goto decompr_got_mlen_n2b */
|
149
|
|
- inc %xCX /* m_len++ */
|
150
|
|
-loop2_n2b:
|
151
|
|
- call getbit1
|
152
|
|
- adc %xCX, %xCX /* m_len = m_len*2 + getbit() */
|
153
|
|
- call getbit1
|
154
|
|
- jnc loop2_n2b /* while(!getbit()) */
|
155
|
|
- inc %xCX
|
156
|
|
- inc %xCX /* m_len += 2 */
|
157
|
|
-decompr_got_mlen_n2b:
|
158
|
|
- cmp $-0xd00, %xBP
|
159
|
|
- adc $1, %xCX /* m_len = m_len + 1 + (last_m_off > 0xd00) */
|
160
|
|
- push %xSI
|
161
|
|
- ADDR32 lea (%xBP,%xDI), %xSI /* m_pos = dst + olen + -m_off */
|
162
|
|
- rep
|
163
|
|
- es ADDR32 movsb /* dst[olen++] = *m_pos++ while(m_len > 0) */
|
164
|
|
- pop %xSI
|
165
|
|
- jmp decompr_loop_n2b
|
166
|
|
-
|
167
|
|
-
|
168
|
|
-getbit1:
|
169
|
|
- addl %ebx, %ebx
|
170
|
|
- jnz 1f
|
171
|
|
-getbit32:
|
172
|
|
- ADDR32 movl (%xSI), %ebx
|
173
|
|
- sub $-4, %xSI /* sets carry flag */
|
174
|
|
- adcl %ebx, %ebx
|
175
|
|
-1:
|
176
|
|
- ret
|
177
|
|
-
|
178
|
|
-decompr_end_n2b:
|
179
|
|
- /* Restore registers and return */
|
180
|
|
- pop %xBP
|
181
|
|
- pop %xCX
|
182
|
|
- popl %ebx
|
183
|
|
- pop %xAX
|
184
|
|
- ret
|