src/liblzma/simple/powerpc.c

   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 = ((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
  51 static lzma_ret
  52 powerpc_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
  60 extern lzma_ret
  61 lzma_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
  69 extern lzma_ret
  70 lzma_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 }