9e052883 |
1 | /* Bra86.c -- Converter for x86 code (BCJ)\r |
2 | 2021-02-09 : Igor Pavlov : Public domain */\r |
3 | \r |
4 | #include "Precomp.h"\r |
5 | \r |
6 | #include "Bra.h"\r |
7 | \r |
8 | #define Test86MSByte(b) ((((b) + 1) & 0xFE) == 0)\r |
9 | \r |
10 | SizeT x86_Convert(Byte *data, SizeT size, UInt32 ip, UInt32 *state, int encoding)\r |
11 | {\r |
12 | SizeT pos = 0;\r |
13 | UInt32 mask = *state & 7;\r |
14 | if (size < 5)\r |
15 | return 0;\r |
16 | size -= 4;\r |
17 | ip += 5;\r |
18 | \r |
19 | for (;;)\r |
20 | {\r |
21 | Byte *p = data + pos;\r |
22 | const Byte *limit = data + size;\r |
23 | for (; p < limit; p++)\r |
24 | if ((*p & 0xFE) == 0xE8)\r |
25 | break;\r |
26 | \r |
27 | {\r |
28 | SizeT d = (SizeT)(p - data) - pos;\r |
29 | pos = (SizeT)(p - data);\r |
30 | if (p >= limit)\r |
31 | {\r |
32 | *state = (d > 2 ? 0 : mask >> (unsigned)d);\r |
33 | return pos;\r |
34 | }\r |
35 | if (d > 2)\r |
36 | mask = 0;\r |
37 | else\r |
38 | {\r |
39 | mask >>= (unsigned)d;\r |
40 | if (mask != 0 && (mask > 4 || mask == 3 || Test86MSByte(p[(size_t)(mask >> 1) + 1])))\r |
41 | {\r |
42 | mask = (mask >> 1) | 4;\r |
43 | pos++;\r |
44 | continue;\r |
45 | }\r |
46 | }\r |
47 | }\r |
48 | \r |
49 | if (Test86MSByte(p[4]))\r |
50 | {\r |
51 | UInt32 v = ((UInt32)p[4] << 24) | ((UInt32)p[3] << 16) | ((UInt32)p[2] << 8) | ((UInt32)p[1]);\r |
52 | UInt32 cur = ip + (UInt32)pos;\r |
53 | pos += 5;\r |
54 | if (encoding)\r |
55 | v += cur;\r |
56 | else\r |
57 | v -= cur;\r |
58 | if (mask != 0)\r |
59 | {\r |
60 | unsigned sh = (mask & 6) << 2;\r |
61 | if (Test86MSByte((Byte)(v >> sh)))\r |
62 | {\r |
63 | v ^= (((UInt32)0x100 << sh) - 1);\r |
64 | if (encoding)\r |
65 | v += cur;\r |
66 | else\r |
67 | v -= cur;\r |
68 | }\r |
69 | mask = 0;\r |
70 | }\r |
71 | p[1] = (Byte)v;\r |
72 | p[2] = (Byte)(v >> 8);\r |
73 | p[3] = (Byte)(v >> 16);\r |
74 | p[4] = (Byte)(0 - ((v >> 24) & 1));\r |
75 | }\r |
76 | else\r |
77 | {\r |
78 | mask = (mask >> 1) | 4;\r |
79 | pos++;\r |
80 | }\r |
81 | }\r |
82 | }\r |