// SPDX-License-Identifier: 0BSD

///////////////////////////////////////////////////////////////////////////////

//

/// \file       powerpc.c

/// \brief      Filter for PowerPC (big endian) binaries

///

//  Authors:    Igor Pavlov

//              Lasse Collin

//

///////////////////////////////////////////////////////////////////////////////

#include "simple_private.h"

static size_t

powerpc_code(void *simple lzma_attribute((__unused__)),

    uint32_t now_pos, bool is_encoder,

    uint8_t *buffer, size_t size)

{

  size &= ~(size_t)3;

  size_t i;

  for (i = 0; i < size; i += 4) {

    // PowerPC branch 6(48) 24(Offset) 1(Abs) 1(Link)

    if ((buffer[i] >> 2) == 0x12

        && ((buffer[i + 3] & 3) == 1)) {

      const uint32_t src

        = (((uint32_t)(buffer[i + 0]) & 3) << 24)

        | ((uint32_t)(buffer[i + 1]) << 16)

        | ((uint32_t)(buffer[i + 2]) << 8)

        | ((uint32_t)(buffer[i + 3]) & ~UINT32_C(3));

      uint32_t dest;

      if (is_encoder)

        dest = now_pos + (uint32_t)(i) + src;

      else

        dest = src - (now_pos + (uint32_t)(i));

      buffer[i + 0] = 0x48 | ((dest >> 24) &  0x03);

      buffer[i + 1] = (dest >> 16);

      buffer[i + 2] = (dest >> 8);

      buffer[i + 3] &= 0x03;

      buffer[i + 3] |= dest;

    }

  }

  return i;

}

static lzma_ret

powerpc_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,

    const lzma_filter_info *filters, bool is_encoder)

{

  return lzma_simple_coder_init(next, allocator, filters,

      &powerpc_code, 0, 4, 4, is_encoder);

}

#ifdef HAVE_ENCODER_POWERPC

extern lzma_ret

lzma_simple_powerpc_encoder_init(lzma_next_coder *next,

    const lzma_allocator *allocator,

    const lzma_filter_info *filters)

{

  return powerpc_coder_init(next, allocator, filters, true);

}

#endif

#ifdef HAVE_DECODER_POWERPC

extern lzma_ret

lzma_simple_powerpc_decoder_init(lzma_next_coder *next,

    const lzma_allocator *allocator,

    const lzma_filter_info *filters)

{

  return powerpc_coder_init(next, allocator, filters, false);

}

#endif