powerpc.c revision 292588 
1///////////////////////////////////////////////////////////////////////////////
2//
3/// \file       powerpc.c
4/// \brief      Filter for PowerPC (big endian) binaries
5///
6//  Authors:    Igor Pavlov
7//              Lasse Collin
8//
9//  This file has been put into the public domain.
10//  You can do whatever you want with this file.
11//
12///////////////////////////////////////////////////////////////////////////////
13
14#include "simple_private.h"
15
16
17static size_t
18powerpc_code(lzma_simple *simple lzma_attribute((__unused__)),
19		uint32_t now_pos, bool is_encoder,
20		uint8_t *buffer, size_t size)
21{
22	size_t i;
23	for (i = 0; i + 4 <= size; i += 4) {
24		// PowerPC branch 6(48) 24(Offset) 1(Abs) 1(Link)
25		if ((buffer[i] >> 2) == 0x12
26				&& ((buffer[i + 3] & 3) == 1)) {
27
28			const uint32_t src = ((buffer[i + 0] & 3) << 24)
29					| (buffer[i + 1] << 16)
30					| (buffer[i + 2] << 8)
31					| (buffer[i + 3] & (~3));
32
33			uint32_t dest;
34			if (is_encoder)
35				dest = now_pos + (uint32_t)(i) + src;
36			else
37				dest = src - (now_pos + (uint32_t)(i));
38
39			buffer[i + 0] = 0x48 | ((dest >> 24) &  0x03);
40			buffer[i + 1] = (dest >> 16);
41			buffer[i + 2] = (dest >> 8);
42			buffer[i + 3] &= 0x03;
43			buffer[i + 3] |= dest;
44		}
45	}
46
47	return i;
48}
49
50
51static lzma_ret
52powerpc_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,
53		const lzma_filter_info *filters, bool is_encoder)
54{
55	return lzma_simple_coder_init(next, allocator, filters,
56			&powerpc_code, 0, 4, 4, is_encoder);
57}
58
59
60extern lzma_ret
61lzma_simple_powerpc_encoder_init(lzma_next_coder *next,
62		const lzma_allocator *allocator,
63		const lzma_filter_info *filters)
64{
65	return powerpc_coder_init(next, allocator, filters, true);
66}
67
68
69extern lzma_ret
70lzma_simple_powerpc_decoder_init(lzma_next_coder *next,
71		const lzma_allocator *allocator,
72		const lzma_filter_info *filters)
73{
74	return powerpc_coder_init(next, allocator, filters, false);
75}
76