75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file armthumb.c
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/// \brief Filter for ARM-Thumb binaries
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///
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// Authors: Igor Pavlov
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// Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "simple_private.h"
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static size_t
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armthumb_code(lzma_simple *simple lzma_attribute((__unused__)),
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uint32_t now_pos, bool is_encoder,
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uint8_t *buffer, size_t size)
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{
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size_t i;
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for (i = 0; i + 4 <= size; i += 2) {
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if ((buffer[i + 1] & 0xF8) == 0xF0
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&& (buffer[i + 3] & 0xF8) == 0xF8) {
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uint32_t src = ((buffer[i + 1] & 0x7) << 19)
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| (buffer[i + 0] << 11)
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| ((buffer[i + 3] & 0x7) << 8)
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| (buffer[i + 2]);
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src <<= 1;
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uint32_t dest;
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if (is_encoder)
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dest = now_pos + (uint32_t)(i) + 4 + src;
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else
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dest = src - (now_pos + (uint32_t)(i) + 4);
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dest >>= 1;
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buffer[i + 1] = 0xF0 | ((dest >> 19) & 0x7);
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buffer[i + 0] = (dest >> 11);
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buffer[i + 3] = 0xF8 | ((dest >> 8) & 0x7);
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buffer[i + 2] = (dest);
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i += 2;
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}
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}
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return i;
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}
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static lzma_ret
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armthumb_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
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const lzma_filter_info *filters, bool is_encoder)
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{
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return lzma_simple_coder_init(next, allocator, filters,
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&armthumb_code, 0, 4, 2, is_encoder);
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}
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extern lzma_ret
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lzma_simple_armthumb_encoder_init(lzma_next_coder *next,
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lzma_allocator *allocator, const lzma_filter_info *filters)
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{
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return armthumb_coder_init(next, allocator, filters, true);
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}
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extern lzma_ret
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lzma_simple_armthumb_decoder_init(lzma_next_coder *next,
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lzma_allocator *allocator, const lzma_filter_info *filters)
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{
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return armthumb_coder_init(next, allocator, filters, false);
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}
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