source: vbox/trunk/src/libs/liblzma-5.4.1/simple/ia64.c@ 100111

///////////////////////////////////////////////////////////////////////////////
//
/// \file       ia64.c
/// \brief      Filter for IA64 (Itanium) binaries
///
//  Authors:    Igor Pavlov
//              Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////

#include "simple_private.h"


static size_t
ia64_code(void *simple lzma_attribute((__unused__)),
                uint32_t now_pos, bool is_encoder,
                uint8_t *buffer, size_t size)
{
        static const uint32_t BRANCH_TABLE[32] = {
                0, 0, 0, 0, 0, 0, 0, 0,
                0, 0, 0, 0, 0, 0, 0, 0,
                4, 4, 6, 6, 0, 0, 7, 7,
                4, 4, 0, 0, 4, 4, 0, 0
        };

        size_t i;
        for (i = 0; i + 16 <= size; i += 16) {
                const uint32_t instr_template = buffer[i] & 0x1F;
                const uint32_t mask = BRANCH_TABLE[instr_template];
                uint32_t bit_pos = 5;

                for (size_t slot = 0; slot < 3; ++slot, bit_pos += 41) {
                        if (((mask >> slot) & 1) == 0)
                                continue;

                        const size_t byte_pos = (bit_pos >> 3);
                        const uint32_t bit_res = bit_pos & 0x7;
                        uint64_t instruction = 0;

                        for (size_t j = 0; j < 6; ++j)
                                instruction += (uint64_t)(
                                                buffer[i + j + byte_pos])
                                                << (8 * j);

                        uint64_t inst_norm = instruction >> bit_res;

                        if (((inst_norm >> 37) & 0xF) == 0x5
                                        && ((inst_norm >> 9) & 0x7) == 0
                                        /* &&  (inst_norm & 0x3F)== 0 */
                                        ) {
                                uint32_t src = (uint32_t)(
                                                (inst_norm >> 13) & 0xFFFFF);
                                src |= ((inst_norm >> 36) & 1) << 20;

                                src <<= 4;

                                uint32_t dest;
                                if (is_encoder)
                                        dest = now_pos + (uint32_t)(i) + src;
                                else
                                        dest = src - (now_pos + (uint32_t)(i));

                                dest >>= 4;

                                inst_norm &= ~((uint64_t)(0x8FFFFF) << 13);
                                inst_norm |= (uint64_t)(dest & 0xFFFFF) << 13;
                                inst_norm |= (uint64_t)(dest & 0x100000)
                                                << (36 - 20);

                                instruction &= (1U << bit_res) - 1;
                                instruction |= (inst_norm << bit_res);

                                for (size_t j = 0; j < 6; j++)
                                        buffer[i + j + byte_pos] = (uint8_t)(
                                                        instruction
                                                        >> (8 * j));
                        }
                }
        }

        return i;
}


static lzma_ret
ia64_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,
                        &ia64_code, 0, 16, 16, is_encoder);
}


#ifdef HAVE_ENCODER_IA64
extern lzma_ret
lzma_simple_ia64_encoder_init(lzma_next_coder *next,
                const lzma_allocator *allocator,
                const lzma_filter_info *filters)
{
        return ia64_coder_init(next, allocator, filters, true);
}
#endif


#ifdef HAVE_DECODER_IA64
extern lzma_ret
lzma_simple_ia64_decoder_init(lzma_next_coder *next,
                const lzma_allocator *allocator,
                const lzma_filter_info *filters)
{
        return ia64_coder_init(next, allocator, filters, false);
}
#endif