disas/arm-a64.cc

   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
  20 #include "a64/disasm-a64.h"
  21
  22 extern "C" {
  23 #include "disas/bfd.h"
  24 }
  25
  26 using namespace vixl;
  27
  28 static Decoder *vixl_decoder = NULL;
  29 static Disassembler *vixl_disasm = NULL;
  30
  31 /* We don't use libvixl's PrintDisassembler because its output
  32  * is a little unhelpful (trailing newlines, for example).
  33  * Instead we use our own very similar variant so we have
  34  * control over the format.
  35  */
  36 class QEMUDisassembler : public Disassembler {
  37 public:
  38     explicit QEMUDisassembler(FILE *stream) : stream_(stream) { }
  39     ~QEMUDisassembler() { }
  40
  41 protected:
  42     void ProcessOutput(Instruction *instr) {
  43         fprintf(stream_, "%08" PRIx32 "      %s",
  44                 instr->InstructionBits(), GetOutput());
  45     }
  46
  47 private:
  48     FILE *stream_;
  49 };
  50
  51 static int vixl_is_initialized(void)
  52 {
  53     return vixl_decoder != NULL;
  54 }
  55
  56 static void vixl_init(FILE *f) {
  57     vixl_decoder = new Decoder();
  58     vixl_disasm = new QEMUDisassembler(f);
  59     vixl_decoder->AppendVisitor(vixl_disasm);
  60 }
  61
  62 #define INSN_SIZE 4
  63
  64 /* Disassemble ARM A64 instruction. This is our only entry
  65  * point from QEMU's C code.
  66  */
  67 int print_insn_arm_a64(uint64_t addr, disassemble_info *info)
  68 {
  69     uint8_t bytes[INSN_SIZE];
  70     uint32_t instr;
  71     int status;
  72
  73     status = info->read_memory_func(addr, bytes, INSN_SIZE, info);
  74     if (status != 0) {
  75         info->memory_error_func(status, addr, info);
  76         return -1;
  77     }
  78
  79     if (!vixl_is_initialized()) {
  80         vixl_init(info->stream);
  81     }
  82
  83     instr = bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24;
  84     vixl_decoder->Decode(reinterpret_cast<Instruction*>(&instr));
  85
  86     return INSN_SIZE;
  87 }