qemu/disas/arm-a64.cc
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   1/*
   2 * ARM A64 disassembly output wrapper to libvixl
   3 * Copyright (c) 2013 Linaro Limited
   4 * Written by Claudio Fontana
   5 *
   6 * This program is free software: you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation, either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20extern "C" {
  21#include "qemu/osdep.h"
  22#include "disas/bfd.h"
  23}
  24
  25#include "vixl/a64/disasm-a64.h"
  26
  27using namespace vixl;
  28
  29static Decoder *vixl_decoder = NULL;
  30static Disassembler *vixl_disasm = NULL;
  31
  32/* We don't use libvixl's PrintDisassembler because its output
  33 * is a little unhelpful (trailing newlines, for example).
  34 * Instead we use our own very similar variant so we have
  35 * control over the format.
  36 */
  37class QEMUDisassembler : public Disassembler {
  38public:
  39    QEMUDisassembler() : printf_(NULL), stream_(NULL) { }
  40    ~QEMUDisassembler() { }
  41
  42    void SetStream(FILE *stream) {
  43        stream_ = stream;
  44    }
  45
  46    void SetPrintf(fprintf_function printf_fn) {
  47        printf_ = printf_fn;
  48    }
  49
  50protected:
  51    virtual void ProcessOutput(const Instruction *instr) {
  52        printf_(stream_, "%08" PRIx32 "      %s",
  53                instr->InstructionBits(), GetOutput());
  54    }
  55
  56private:
  57    fprintf_function printf_;
  58    FILE *stream_;
  59};
  60
  61static int vixl_is_initialized(void)
  62{
  63    return vixl_decoder != NULL;
  64}
  65
  66static void vixl_init() {
  67    vixl_decoder = new Decoder();
  68    vixl_disasm = new QEMUDisassembler();
  69    vixl_decoder->AppendVisitor(vixl_disasm);
  70}
  71
  72#define INSN_SIZE 4
  73
  74/* Disassemble ARM A64 instruction. This is our only entry
  75 * point from QEMU's C code.
  76 */
  77int print_insn_arm_a64(uint64_t addr, disassemble_info *info)
  78{
  79    uint8_t bytes[INSN_SIZE];
  80    uint32_t instrval;
  81    const Instruction *instr;
  82    int status;
  83
  84    status = info->read_memory_func(addr, bytes, INSN_SIZE, info);
  85    if (status != 0) {
  86        info->memory_error_func(status, addr, info);
  87        return -1;
  88    }
  89
  90    if (!vixl_is_initialized()) {
  91        vixl_init();
  92    }
  93
  94    ((QEMUDisassembler *)vixl_disasm)->SetPrintf(info->fprintf_func);
  95    ((QEMUDisassembler *)vixl_disasm)->SetStream(info->stream);
  96
  97    instrval = bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24;
  98    instr = reinterpret_cast<const Instruction *>(&instrval);
  99    vixl_disasm->MapCodeAddress(addr, instr);
 100    vixl_decoder->Decode(instr);
 101
 102    return INSN_SIZE;
 103}
 104