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  
      17  static size_t
      18  powerpc_code(void *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
      29  				= (((uint32_t)(buffer[i + 0]) & 3) << 24)
      30  				| ((uint32_t)(buffer[i + 1]) << 16)
      31  				| ((uint32_t)(buffer[i + 2]) << 8)
      32  				| ((uint32_t)(buffer[i + 3]) & ~UINT32_C(3));
      33  
      34  			uint32_t dest;
      35  			if (is_encoder)
      36  				dest = now_pos + (uint32_t)(i) + src;
      37  			else
      38  				dest = src - (now_pos + (uint32_t)(i));
      39  
      40  			buffer[i + 0] = 0x48 | ((dest >> 24) &  0x03);
      41  			buffer[i + 1] = (dest >> 16);
      42  			buffer[i + 2] = (dest >> 8);
      43  			buffer[i + 3] &= 0x03;
      44  			buffer[i + 3] |= dest;
      45  		}
      46  	}
      47  
      48  	return i;
      49  }
      50  
      51  
      52  static lzma_ret
      53  powerpc_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,
      54  		const lzma_filter_info *filters, bool is_encoder)
      55  {
      56  	return lzma_simple_coder_init(next, allocator, filters,
      57  			&powerpc_code, 0, 4, 4, is_encoder);
      58  }
      59  
      60  
      61  #ifdef HAVE_ENCODER_POWERPC
      62  extern lzma_ret
      63  lzma_simple_powerpc_encoder_init(lzma_next_coder *next,
      64  		const lzma_allocator *allocator,
      65  		const lzma_filter_info *filters)
      66  {
      67  	return powerpc_coder_init(next, allocator, filters, true);
      68  }
      69  #endif
      70  
      71  
      72  #ifdef HAVE_DECODER_POWERPC
      73  extern lzma_ret
      74  lzma_simple_powerpc_decoder_init(lzma_next_coder *next,
      75  		const lzma_allocator *allocator,
      76  		const lzma_filter_info *filters)
      77  {
      78  	return powerpc_coder_init(next, allocator, filters, false);
      79  }
      80  #endif