decoder.c

基于linux的DVD播放器程序

  }
  return 0;
}


/* Evaluate set operation
   Sets the register given to the value indicated by op and data.
   For the swap case the contents of reg is stored in reg2.
*/
static void eval_set_op(int op, int reg, int reg2, int data)
{
  /* General parameters and System Parameters (GPRMS and SPRMS)
   * are treated as 16-bit unsigned integers.
   * in case of overflow, 0xFFFF must be assigned
   * in case of underflow, 0x0 must be assigned
   */
  const int shortmax = 0xffff;
  
  int tmp;
  switch(op) {
    case 1: /* = (assignment) */
      state->GPRM[reg] = data;
      break;
    case 2: /* Swap */
      tmp = state->GPRM[reg];
      state->GPRM[reg] = state->GPRM[reg2];
      state->GPRM[reg2] = tmp;
      break;
    case 3: /* += (addition) */
      tmp = state->GPRM[reg] + data;
      if(tmp >= shortmax) tmp = shortmax;
      state->GPRM[reg] = (uint16_t)tmp;
      break;
    case 4: /* -= (subtraction) */
      tmp = state->GPRM[reg] - data;
      if(tmp < 0) tmp = 0;
      state->GPRM[reg] = (uint16_t)tmp;      
      break;
    case 5: /* *= (multiplication) */
      tmp = state->GPRM[reg] * data;
      if(tmp >= shortmax) tmp = shortmax;
      state->GPRM[reg] = (uint16_t)tmp;
      break;
    case 6: /* /= (division) */
      if(data != 0)
	state->GPRM[reg] /= data;
      else
	state->GPRM[reg] = 65535;
      break;
    case 7: /* %= (modulo) */
      if(data != 0)
	state->GPRM[reg] %= data;
      else
	state->GPRM[reg] = 0; /* really an error I guess */
      break;
      break;
    case 8: /* SPECIAL CASE - RANDOM! */
      if(data != 0)
	/* TODO rand() might only return 0-32768  */
	state->GPRM[reg] = (rand() % data) + 1;
      else
	state->GPRM[reg] = 0; /* really an error I guess */
      break;
    case 9: /* &= (bitwise and) */
      state->GPRM[reg] &= data;
      break;
    case 10: /* |= (bitwise or) */
      state->GPRM[reg] |= data;
      break;
    case 11: /* ^= (bitwise xor) */
      state->GPRM[reg] ^= data;
      break;
  }
}

/* Evaluate set instruction, combined with either Link or Compare. 
 * PPP0SSSS ******** ******** 0AAAAAAA ******** BBBBBBBB ******** ********
 * PPP1SSSS ******** ******** 0AAAAAAA DDDDDDDD DDDDDDDD ******** ********
 * where PPP is 011
 * "r[A] `S` r[B]" resp "r[A] `S` D"
 */
static void eval_set_version_1(int cond)
{
  uint8_t  op   = bits(0, 4, 4);
  uint8_t  reg  = bits(3, 0, 8); // GPRM
  uint8_t  reg2 = bits(5, 4, 4); // GPRM or SPRM
  uint16_t data = eval_reg_or_data(bits(0, 3, 1), 4); // or Imm

  if(cond) {
    eval_set_op(op, reg, reg2, data);
  }
}


/* Evaluate set instruction for Set Compare Link.
 * PPP0SSSS ****AAAA ******** BBBBBBBB ******** ******** ******** ********
 * PPP1SSSS ****AAAA DDDDDDDD DDDDDDDD ******** ******** ******** ********
 * when PPP is 101
 * "g[A] `S` r[B]" resp "g[A] `S` D"
 */
static void eval_set_version_2(int cond)
{
  uint8_t  op   = bits(0, 4, 4);
  uint8_t  reg  = bits(1, 4, 4); // GPRM
  uint8_t  reg2 = bits(3, 0, 8); // GPRM or SPRM
  uint16_t data = eval_reg_or_data(bits(0, 3, 1), 2); // or Imm

  if(cond) {
    eval_set_op(op, reg, reg2, data);
  }
}

/* Evaluate set instruction for, Compare & Set-Link, Compare-Set & Link. 
 * PPP0SSSS ****AAAA BBBBBBBB ******** ******** ******** ******** ********
 * PPP1SSSS 0***AAAA DDDDDDDD DDDDDDDD ******** ******** ******** ********
 * when PPP is 100 or 110
 * "g[A] `S` r[B]" resp "g[A] `S` D"
 */
static void eval_set_version_3(int cond)
{
  uint8_t  op   = bits(0, 4, 4);
  uint8_t  reg  = bits(1, 4, 4); // GPRM
  uint8_t  reg2 = bits(2, 0, 8); // GPRM or SPRM
  uint16_t data;
  if(bits(0, 3, 1)) { // immediate
    data = bits(2, 0, 16);
  } else {
    data = eval_reg(reg2);
  }

  if(cond) {
    eval_set_op(op, reg, reg2, data);
  }
}


/* Evaluate a command
   returns row number of goto, 0 if no goto, -1 if link.
   Link command in return_values */
static int eval_command(uint8_t *bytes, link_t *return_values)
{
  int i, extra_bits;
  int cond, res = 0;

  for(i = 0; i < 8; i++) {
    cmd.bits[i] = bytes[i];
    cmd.examined[i] = 0;
  }
  memset(return_values, 0, sizeof(link_t));

  switch(bits(0, 0, 3)) { /* three first bits */
    case 0: // Special instructions
      cond = eval_if_version_1();
      res = eval_special_instruction(cond);
      if(res == -1) {
	fprintf(stderr, "Unknown Instruction!\n");
	//exit(0);
      }
      break;
    case 1: // Link/jump instructions
      if(bits(0, 3, 1)) {
        cond = eval_if_version_2();
        res = eval_jump_instruction(cond, return_values);
      } else {
        cond = eval_if_version_1();
        res = eval_link_instruction(cond, return_values);
      }
      if(res)
	res = -1;
      break;
    case 2: // System set instructions
      cond = eval_if_version_2();
      res = eval_system_set(cond, return_values);
      if(res)
	res = -1;
      break;
    case 3: // Set instructions, either Compare or Link may be used
      cond = eval_if_version_3();
      eval_set_version_1(cond);
      if(bits(1, 4, 4)) {
	res = eval_link_instruction(cond, return_values);
      }
      if(res)
	res = -1;
      break;
    case 4: // Set, Compare -> Link Sub-Instruction
      eval_set_version_2(/*True*/ 1);
      cond = eval_if_version_4();
      res = eval_link_subins(cond, return_values);
      if(res)
	res = -1;
      break;
    case 5: // Compare -> (Set and Link Sub-Instruction)
      if(bits(0, 3, 1))
	cond = eval_if_version_5();
      else
	cond = eval_if_version_1();
      eval_set_version_3(cond);
      res = eval_link_subins(cond, return_values);
      if(res)
	res = -1;
      break;
    case 6: // Compare -> Set, always Link Sub-Instruction
      if(bits(0, 3, 1))
	cond = eval_if_version_5();
      else
	cond = eval_if_version_1();
      eval_set_version_3(cond);
      res = eval_link_subins(/*True*/ 1, return_values);
      if(res)
	res = -1;
      break;
  }
  // Check if there are bits not yet examined

  extra_bits = 0;
  for(i = 0; i < 8; i++)
    if(cmd.bits [i] & ~cmd.examined [i]) {
      extra_bits = 1;
      break;
    }
  if(extra_bits) {
    fprintf(stderr, "[WARNING, unknown bits:");
    for(i = 0; i < 8; i++)
      fprintf(stderr, " %02x", cmd.bits [i] & ~cmd.examined [i]);
    fprintf(stderr, "]\n");
  }

  return res;
}

/* Evaluate a set of commands in the given register set (which is
 * modified */
int vmEval_CMD(vm_cmd_t commands[], int num_commands, 
	       registers_t *registers, link_t *return_values)
{
  int i = 0;
  int total = 0;
  
  state = registers; // TODO FIXME

#ifdef TRACE
  // DEBUG
  if(1) {
    int i;
    fprintf(stderr, "   #   ");
    for(i = 0; i < 24; i++)
    fprintf(stderr, " %2d |", i);
    fprintf(stderr, "\nSPRMS: ");
    for(i = 0; i < 24; i++)
      fprintf(stderr, "%04x|", state->SPRM[i]);
    fprintf(stderr, "\nGPRMS: ");
    for(i = 0; i < 16; i++)
      fprintf(stderr, "%04x|", state->GPRM[i]);
    fprintf(stderr, "\n");
  }
  if(1) {
    int i;
    for(i = 0; i < num_commands; i++)
      vmPrint_CMD(i, &commands[i]);
    fprintf(stderr, "--------------------------------------------\n");
  } // end DEBUG
#endif
  
  while(i < num_commands && total < 100000) {
    int line;
    
    if(0) vmPrint_CMD(i, &commands[i]);
    line = eval_command(&commands[i].bytes[0], return_values);
    
    if (line < 0) { // Link command
#ifdef TRACE
      fprintf(stderr, "eval: Doing Link/Jump/Call\n");
#endif
      return 1;
    }
    
    if (line > 0) // Goto command
      i = line - 1;
    else // Just continue on the next line
      i++;

    total++;
  }
  
  memset(return_values, 0, sizeof(link_t));
  return 0;
}


static char *linkcmd2str(link_cmd_t cmd)
{
  switch(cmd) {
  case LinkNoLink:
    return "LinkNoLink";
  case LinkTopC:
    return "LinkTopC";
  case LinkNextC:
    return "LinkNextC";
  case LinkPrevC:
    return "LinkPrevC";
  case LinkTopPG:
    return "LinkTopPG";
  case LinkNextPG:
    return "LinkNextPG";
  case LinkPrevPG:
    return "LinkPrevPG";
  case LinkTopPGC:
    return "LinkTopPGC";
  case LinkNextPGC:
    return "LinkNextPGC";
  case LinkPrevPGC:
    return "LinkPrevPGC";
  case LinkGoUpPGC:
    return "LinkGoUpPGC";
  case LinkTailPGC:
    return "LinkTailPGC";
  case LinkRSM:
    return "LinkRSM";
  case LinkPGCN:
    return "LinkPGCN";
  case LinkPTTN:
    return "LinkPTTN";
  case LinkPGN:
    return "LinkPGN";
  case LinkCN:
    return "LinkCN";
  case Exit:
    return "Exit";
  case JumpTT:
    return "JumpTT";
  case JumpVTS_TT:
    return "JumpVTS_TT";
  case JumpVTS_PTT:
    return "JumpVTS_PTT";
  case JumpSS_FP:
    return "JumpSS_FP";
  case JumpSS_VMGM_MENU:
    return "JumpSS_VMGM_MENU";
  case JumpSS_VTSM:
    return "JumpSS_VTSM";
  case JumpSS_VMGM_PGC:
    return "JumpSS_VMGM_PGC";
  case CallSS_FP:
    return "CallSS_FP";
  case CallSS_VMGM_MENU:
    return "CallSS_VMGM_MENU";
  case CallSS_VTSM:
    return "CallSS_VTSM";
  case CallSS_VMGM_PGC:
    return "CallSS_VMGM_PGC";
  case PlayThis:
    return "PlayThis";
  }
  return "*** (bug)";
}

void vmPrint_LINK(link_t value)
{
  char *cmd = linkcmd2str(value.command);
    
  switch(value.command) {
  case LinkNoLink:
  case LinkTopC:
  case LinkNextC:
  case LinkPrevC:
  case LinkTopPG:
  case LinkNextPG:
  case LinkPrevPG:
  case LinkTopPGC:
  case LinkNextPGC:
  case LinkPrevPGC:
  case LinkGoUpPGC:
  case LinkTailPGC:
  case LinkRSM:
    fprintf(stderr, "%s (button %d)\n", cmd, value.data1);
    break;
  case LinkPGCN:
  case JumpTT:
  case JumpVTS_TT:
  case JumpSS_VMGM_MENU: // == 2 -> Title Menu
  case JumpSS_VMGM_PGC:
    fprintf(stderr, "%s %d\n", cmd, value.data1);
    break;
  case LinkPTTN:
  case LinkPGN:
  case LinkCN:
    fprintf(stderr, "%s %d (button %d)\n", cmd, value.data1, value.data2);
    break;
  case Exit:
  case JumpSS_FP:
  case PlayThis: // Humm.. should we have this at all..
    fprintf(stderr, "%s\n", cmd);
    break;
  case JumpVTS_PTT:
    fprintf(stderr, "%s %d:%d\n", cmd, value.data1, value.data2);
    break;
  case JumpSS_VTSM:
    fprintf(stderr, "%s vts %d title %d menu %d\n", 
	    cmd, value.data1, value.data2, value.data3);
    break;
  case CallSS_FP:
    fprintf(stderr, "%s resume cell %d\n", cmd, value.data1);
    break;
  case CallSS_VMGM_MENU: // == 2 -> Title Menu
  case CallSS_VTSM:
    fprintf(stderr, "%s %d resume cell %d\n", cmd, value.data1, value.data2);
    break;
  case CallSS_VMGM_PGC:
    fprintf(stderr, "%s %d resume cell %d\n", cmd, value.data1, value.data2);
    break;
  }
}