#ifdef CPUCORE_CPP

uint8 CPUcore::dreadb(uint32 addr) {
  if((addr & 0x40ffff) >= 0x2000 && (addr & 0x40ffff) <= 0x5fff) {
    //$[00-3f|80-bf]:[2000-5fff]
    //do not read MMIO registers within debugger
    return 0x00;
  }
  return bus.read(addr);
}

uint16 CPUcore::dreadw(uint32 addr) {
  uint16 r;
  r  = dreadb((addr + 0) & 0xffffff) <<  0;
  r |= dreadb((addr + 1) & 0xffffff) <<  8;
  return r;
}

uint32 CPUcore::dreadl(uint32 addr) {
  uint32 r;
  r  = dreadb((addr + 0) & 0xffffff) <<  0;
  r |= dreadb((addr + 1) & 0xffffff) <<  8;
  r |= dreadb((addr + 2) & 0xffffff) << 16;
  return r;
}

uint32 CPUcore::decode(uint8 offset_type, uint32 addr) {
  uint32 r = 0;

  switch(offset_type) {
    case OPTYPE_DP:
      r = (regs.d + (addr & 0xffff)) & 0xffff;
      break;
    case OPTYPE_DPX:
      r = (regs.d + regs.x + (addr & 0xffff)) & 0xffff;
      break;
    case OPTYPE_DPY:
      r = (regs.d + regs.y + (addr & 0xffff)) & 0xffff;
      break;
    case OPTYPE_IDP:
      addr = (regs.d + (addr & 0xffff)) & 0xffff;
      r = (regs.db << 16) + dreadw(addr);
      break;
    case OPTYPE_IDPX:
      addr = (regs.d + regs.x + (addr & 0xffff)) & 0xffff;
      r = (regs.db << 16) + dreadw(addr);
      break;
    case OPTYPE_IDPY:
      addr = (regs.d + (addr & 0xffff)) & 0xffff;
      r = (regs.db << 16) + dreadw(addr) + regs.y;
      break;
    case OPTYPE_ILDP:
      addr = (regs.d + (addr & 0xffff)) & 0xffff;
      r = dreadl(addr);
      break;
    case OPTYPE_ILDPY:
      addr = (regs.d + (addr & 0xffff)) & 0xffff;
      r = dreadl(addr) + regs.y;
      break;
    case OPTYPE_ADDR:
      r = (regs.db << 16) + (addr & 0xffff);
      break;
    case OPTYPE_ADDR_PC:
      r = (regs.pc.b << 16) + (addr & 0xffff);
      break;
    case OPTYPE_ADDRX:
      r = (regs.db << 16) + (addr & 0xffff) + regs.x;
      break;
    case OPTYPE_ADDRY:
      r = (regs.db << 16) + (addr & 0xffff) + regs.y;
      break;
    case OPTYPE_IADDR_PC:
      r = (regs.pc.b << 16) + (addr & 0xffff);
      break;
    case OPTYPE_IADDRX:
      r = (regs.pc.b << 16) + ((addr + regs.x) & 0xffff);
      break;
    case OPTYPE_ILADDR:
      r = addr;
      break;
    case OPTYPE_LONG:
      r = addr;
      break;
    case OPTYPE_LONGX:
      r = (addr + regs.x);
      break;
    case OPTYPE_SR:
      r = (regs.s + (addr & 0xff)) & 0xffff;
      break;
    case OPTYPE_ISRY:
      addr = (regs.s + (addr & 0xff)) & 0xffff;
      r = (regs.db << 16) + dreadw(addr) + regs.y;
      break;
    case OPTYPE_RELB:
      r  = (regs.pc.b << 16) + ((regs.pc.w + 2) & 0xffff);
      r += int8(addr);
      break;
    case OPTYPE_RELW:
      r  = (regs.pc.b << 16) + ((regs.pc.w + 3) & 0xffff);
      r += int16(addr);
      break;
  }

  return(r & 0xffffff);
}

void CPUcore::disassemble_opcode(char *output, uint32 addr) {
  static reg24_t pc;
  char t[256];
  char *s = output;

  if(false /* in_opcode() == true */) {
    strcpy(s, "?????? <CPU within opcode>");
    return;
  }

  pc.d = addr;
  sprintf(s, "%.6x ", (uint32)pc.d);

  uint8 op  = dreadb(pc.d); pc.w++;
  uint8 op0 = dreadb(pc.d); pc.w++;
  uint8 op1 = dreadb(pc.d); pc.w++;
  uint8 op2 = dreadb(pc.d);

  #define op8  ((op0))
  #define op16 ((op0) | (op1 << 8))
  #define op24 ((op0) | (op1 << 8) | (op2 << 16))
  #define a8   (regs.e || regs.p.m)
  #define x8   (regs.e || regs.p.x)

  switch(op) {
    case 0x00: sprintf(t, "brk #$%.2x              ", op8); break;
    case 0x01: sprintf(t, "ora ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0x02: sprintf(t, "cop #$%.2x              ", op8); break;
    case 0x03: sprintf(t, "ora $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0x04: sprintf(t, "tsb $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x05: sprintf(t, "ora $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x06: sprintf(t, "asl $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x07: sprintf(t, "ora [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0x08: sprintf(t, "php                   "); break;
    case 0x09: if(a8)sprintf(t, "ora #$%.2x              ", op8);
               else  sprintf(t, "ora #$%.4x            ", op16); break;
    case 0x0a: sprintf(t, "asl a                 "); break;
    case 0x0b: sprintf(t, "phd                   "); break;
    case 0x0c: sprintf(t, "tsb $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x0d: sprintf(t, "ora $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x0e: sprintf(t, "asl $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x0f: sprintf(t, "ora $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x10: sprintf(t, "bpl $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0x11: sprintf(t, "ora ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0x12: sprintf(t, "ora ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0x13: sprintf(t, "ora ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0x14: sprintf(t, "trb $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x15: sprintf(t, "ora $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x16: sprintf(t, "asl $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x17: sprintf(t, "ora [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0x18: sprintf(t, "clc                   "); break;
    case 0x19: sprintf(t, "ora $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0x1a: sprintf(t, "inc                   "); break;
    case 0x1b: sprintf(t, "tcs                   "); break;
    case 0x1c: sprintf(t, "trb $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x1d: sprintf(t, "ora $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x1e: sprintf(t, "asl $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x1f: sprintf(t, "ora $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0x20: sprintf(t, "jsr $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR_PC, op16)); break;
    case 0x21: sprintf(t, "and ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0x22: sprintf(t, "jsl $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x23: sprintf(t, "and $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0x24: sprintf(t, "bit $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x25: sprintf(t, "and $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x26: sprintf(t, "rol $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x27: sprintf(t, "and [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0x28: sprintf(t, "plp                   "); break;
    case 0x29: if(a8)sprintf(t, "and #$%.2x              ", op8);
               else  sprintf(t, "and #$%.4x            ", op16); break;
    case 0x2a: sprintf(t, "rol a                 "); break;
    case 0x2b: sprintf(t, "pld                   "); break;
    case 0x2c: sprintf(t, "bit $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x2d: sprintf(t, "and $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x2e: sprintf(t, "rol $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x2f: sprintf(t, "and $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x30: sprintf(t, "bmi $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0x31: sprintf(t, "and ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0x32: sprintf(t, "and ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0x33: sprintf(t, "and ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0x34: sprintf(t, "bit $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x35: sprintf(t, "and $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x36: sprintf(t, "rol $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x37: sprintf(t, "and [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0x38: sprintf(t, "sec                   "); break;
    case 0x39: sprintf(t, "and $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0x3a: sprintf(t, "dec                   "); break;
    case 0x3b: sprintf(t, "tsc                   "); break;
    case 0x3c: sprintf(t, "bit $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x3d: sprintf(t, "and $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x3e: sprintf(t, "rol $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x3f: sprintf(t, "and $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0x40: sprintf(t, "rti                   "); break;
    case 0x41: sprintf(t, "eor ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0x42: sprintf(t, "wdm                   "); break;
    case 0x43: sprintf(t, "eor $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0x44: sprintf(t, "mvp $%.2x,$%.2x           ", op1, op8); break;
    case 0x45: sprintf(t, "eor $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x46: sprintf(t, "lsr $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x47: sprintf(t, "eor [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0x48: sprintf(t, "pha                   "); break;
    case 0x49: if(a8)sprintf(t, "eor #$%.2x              ", op8);
               else  sprintf(t, "eor #$%.4x            ", op16); break;
    case 0x4a: sprintf(t, "lsr a                 "); break;
    case 0x4b: sprintf(t, "phk                   "); break;
    case 0x4c: sprintf(t, "jmp $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR_PC, op16)); break;
    case 0x4d: sprintf(t, "eor $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x4e: sprintf(t, "lsr $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x4f: sprintf(t, "eor $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x50: sprintf(t, "bvc $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0x51: sprintf(t, "eor ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0x52: sprintf(t, "eor ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0x53: sprintf(t, "eor ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0x54: sprintf(t, "mvn $%.2x,$%.2x           ", op1, op8); break;
    case 0x55: sprintf(t, "eor $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x56: sprintf(t, "lsr $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x57: sprintf(t, "eor [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0x58: sprintf(t, "cli                   "); break;
    case 0x59: sprintf(t, "eor $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0x5a: sprintf(t, "phy                   "); break;
    case 0x5b: sprintf(t, "tcd                   "); break;
    case 0x5c: sprintf(t, "jml $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x5d: sprintf(t, "eor $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x5e: sprintf(t, "lsr $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x5f: sprintf(t, "eor $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0x60: sprintf(t, "rts                   "); break;
    case 0x61: sprintf(t, "adc ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0x62: sprintf(t, "per $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x63: sprintf(t, "adc $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0x64: sprintf(t, "stz $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x65: sprintf(t, "adc $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x66: sprintf(t, "ror $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x67: sprintf(t, "adc [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0x68: sprintf(t, "pla                   "); break;
    case 0x69: if(a8)sprintf(t, "adc #$%.2x              ", op8);
               else  sprintf(t, "adc #$%.4x            ", op16); break;
    case 0x6a: sprintf(t, "ror a                 "); break;
    case 0x6b: sprintf(t, "rtl                   "); break;
    case 0x6c: sprintf(t, "jmp ($%.4x)   [%.6x]", op16, decode(OPTYPE_IADDR_PC, op16)); break;
    case 0x6d: sprintf(t, "adc $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x6e: sprintf(t, "ror $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x6f: sprintf(t, "adc $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x70: sprintf(t, "bvs $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0x71: sprintf(t, "adc ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0x72: sprintf(t, "adc ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0x73: sprintf(t, "adc ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0x74: sprintf(t, "stz $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x75: sprintf(t, "adc $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x76: sprintf(t, "ror $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x77: sprintf(t, "adc [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0x78: sprintf(t, "sei                   "); break;
    case 0x79: sprintf(t, "adc $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0x7a: sprintf(t, "ply                   "); break;
    case 0x7b: sprintf(t, "tdc                   "); break;
    case 0x7c: sprintf(t, "jmp ($%.4x,x) [%.6x]", op16, decode(OPTYPE_IADDRX, op16)); break;
    case 0x7d: sprintf(t, "adc $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x7e: sprintf(t, "ror $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x7f: sprintf(t, "adc $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0x80: sprintf(t, "bra $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0x81: sprintf(t, "sta ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0x82: sprintf(t, "brl $%.4x     [%.6x]", uint16(decode(OPTYPE_RELW, op16)), decode(OPTYPE_RELW, op16)); break;
    case 0x83: sprintf(t, "sta $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0x84: sprintf(t, "sty $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x85: sprintf(t, "sta $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x86: sprintf(t, "stx $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0x87: sprintf(t, "sta [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0x88: sprintf(t, "dey                   "); break;
    case 0x89: if(a8)sprintf(t, "bit #$%.2x              ", op8);
               else  sprintf(t, "bit #$%.4x            ", op16); break;
    case 0x8a: sprintf(t, "txa                   "); break;
    case 0x8b: sprintf(t, "phb                   "); break;
    case 0x8c: sprintf(t, "sty $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x8d: sprintf(t, "sta $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x8e: sprintf(t, "stx $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x8f: sprintf(t, "sta $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0x90: sprintf(t, "bcc $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0x91: sprintf(t, "sta ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0x92: sprintf(t, "sta ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0x93: sprintf(t, "sta ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0x94: sprintf(t, "sty $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x95: sprintf(t, "sta $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0x96: sprintf(t, "stx $%.2x,y     [%.6x]", op8, decode(OPTYPE_DPY, op8)); break;
    case 0x97: sprintf(t, "sta [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0x98: sprintf(t, "tya                   "); break;
    case 0x99: sprintf(t, "sta $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0x9a: sprintf(t, "txs                   "); break;
    case 0x9b: sprintf(t, "txy                   "); break;
    case 0x9c: sprintf(t, "stz $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0x9d: sprintf(t, "sta $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x9e: sprintf(t, "stz $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0x9f: sprintf(t, "sta $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0xa0: if(x8)sprintf(t, "ldy #$%.2x              ", op8);
               else  sprintf(t, "ldy #$%.4x            ", op16); break;
    case 0xa1: sprintf(t, "lda ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0xa2: if(x8)sprintf(t, "ldx #$%.2x              ", op8);
               else  sprintf(t, "ldx #$%.4x            ", op16); break;
    case 0xa3: sprintf(t, "lda $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0xa4: sprintf(t, "ldy $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xa5: sprintf(t, "lda $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xa6: sprintf(t, "ldx $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xa7: sprintf(t, "lda [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0xa8: sprintf(t, "tay                   "); break;
    case 0xa9: if(a8)sprintf(t, "lda #$%.2x              ", op8);
               else  sprintf(t, "lda #$%.4x            ", op16); break;
    case 0xaa: sprintf(t, "tax                   "); break;
    case 0xab: sprintf(t, "plb                   "); break;
    case 0xac: sprintf(t, "ldy $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xad: sprintf(t, "lda $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xae: sprintf(t, "ldx $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xaf: sprintf(t, "lda $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0xb0: sprintf(t, "bcs $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0xb1: sprintf(t, "lda ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0xb2: sprintf(t, "lda ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0xb3: sprintf(t, "lda ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0xb4: sprintf(t, "ldy $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0xb5: sprintf(t, "lda $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0xb6: sprintf(t, "ldx $%.2x,y     [%.6x]", op8, decode(OPTYPE_DPY, op8)); break;
    case 0xb7: sprintf(t, "lda [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0xb8: sprintf(t, "clv                   "); break;
    case 0xb9: sprintf(t, "lda $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0xba: sprintf(t, "tsx                   "); break;
    case 0xbb: sprintf(t, "tyx                   "); break;
    case 0xbc: sprintf(t, "ldy $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0xbd: sprintf(t, "lda $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0xbe: sprintf(t, "ldx $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0xbf: sprintf(t, "lda $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0xc0: if(x8)sprintf(t, "cpy #$%.2x              ", op8);
               else  sprintf(t, "cpy #$%.4x            ", op16); break;
    case 0xc1: sprintf(t, "cmp ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0xc2: sprintf(t, "rep #$%.2x              ", op8); break;
    case 0xc3: sprintf(t, "cmp $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0xc4: sprintf(t, "cpy $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xc5: sprintf(t, "cmp $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xc6: sprintf(t, "dec $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xc7: sprintf(t, "cmp [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0xc8: sprintf(t, "iny                   "); break;
    case 0xc9: if(a8)sprintf(t, "cmp #$%.2x              ", op8);
               else  sprintf(t, "cmp #$%.4x            ", op16); break;
    case 0xca: sprintf(t, "dex                   "); break;
    case 0xcb: sprintf(t, "wai                   "); break;
    case 0xcc: sprintf(t, "cpy $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xcd: sprintf(t, "cmp $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xce: sprintf(t, "dec $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xcf: sprintf(t, "cmp $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0xd0: sprintf(t, "bne $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0xd1: sprintf(t, "cmp ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0xd2: sprintf(t, "cmp ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0xd3: sprintf(t, "cmp ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0xd4: sprintf(t, "pei ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0xd5: sprintf(t, "cmp $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0xd6: sprintf(t, "dec $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0xd7: sprintf(t, "cmp [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0xd8: sprintf(t, "cld                   "); break;
    case 0xd9: sprintf(t, "cmp $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0xda: sprintf(t, "phx                   "); break;
    case 0xdb: sprintf(t, "stp                   "); break;
    case 0xdc: sprintf(t, "jmp [$%.4x]   [%.6x]", op16, decode(OPTYPE_ILADDR, op16)); break;
    case 0xdd: sprintf(t, "cmp $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0xde: sprintf(t, "dec $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0xdf: sprintf(t, "cmp $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
    case 0xe0: if(x8)sprintf(t, "cpx #$%.2x              ", op8);
               else  sprintf(t, "cpx #$%.4x            ", op16); break;
    case 0xe1: sprintf(t, "sbc ($%.2x,x)   [%.6x]", op8, decode(OPTYPE_IDPX, op8)); break;
    case 0xe2: sprintf(t, "sep #$%.2x              ", op8); break;
    case 0xe3: sprintf(t, "sbc $%.2x,s     [%.6x]", op8, decode(OPTYPE_SR, op8)); break;
    case 0xe4: sprintf(t, "cpx $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xe5: sprintf(t, "sbc $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xe6: sprintf(t, "inc $%.2x       [%.6x]", op8, decode(OPTYPE_DP, op8)); break;
    case 0xe7: sprintf(t, "sbc [$%.2x]     [%.6x]", op8, decode(OPTYPE_ILDP, op8)); break;
    case 0xe8: sprintf(t, "inx                   "); break;
    case 0xe9: if(a8)sprintf(t, "sbc #$%.2x              ", op8);
               else  sprintf(t, "sbc #$%.4x            ", op16); break;
    case 0xea: sprintf(t, "nop                   "); break;
    case 0xeb: sprintf(t, "xba                   "); break;
    case 0xec: sprintf(t, "cpx $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xed: sprintf(t, "sbc $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xee: sprintf(t, "inc $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xef: sprintf(t, "sbc $%.6x   [%.6x]", op24, decode(OPTYPE_LONG, op24)); break;
    case 0xf0: sprintf(t, "beq $%.4x     [%.6x]", uint16(decode(OPTYPE_RELB, op8)), decode(OPTYPE_RELB, op8)); break;
    case 0xf1: sprintf(t, "sbc ($%.2x),y   [%.6x]", op8, decode(OPTYPE_IDPY, op8)); break;
    case 0xf2: sprintf(t, "sbc ($%.2x)     [%.6x]", op8, decode(OPTYPE_IDP, op8)); break;
    case 0xf3: sprintf(t, "sbc ($%.2x,s),y [%.6x]", op8, decode(OPTYPE_ISRY, op8)); break;
    case 0xf4: sprintf(t, "pea $%.4x     [%.6x]", op16, decode(OPTYPE_ADDR, op16)); break;
    case 0xf5: sprintf(t, "sbc $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0xf6: sprintf(t, "inc $%.2x,x     [%.6x]", op8, decode(OPTYPE_DPX, op8)); break;
    case 0xf7: sprintf(t, "sbc [$%.2x],y   [%.6x]", op8, decode(OPTYPE_ILDPY, op8)); break;
    case 0xf8: sprintf(t, "sed                   "); break;
    case 0xf9: sprintf(t, "sbc $%.4x,y   [%.6x]", op16, decode(OPTYPE_ADDRY, op16)); break;
    case 0xfa: sprintf(t, "plx                   "); break;
    case 0xfb: sprintf(t, "xce                   "); break;
    case 0xfc: sprintf(t, "jsr ($%.4x,x) [%.6x]", op16, decode(OPTYPE_IADDRX, op16)); break;
    case 0xfd: sprintf(t, "sbc $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0xfe: sprintf(t, "inc $%.4x,x   [%.6x]", op16, decode(OPTYPE_ADDRX, op16)); break;
    case 0xff: sprintf(t, "sbc $%.6x,x [%.6x]", op24, decode(OPTYPE_LONGX, op24)); break;
  }

  #undef op8
  #undef op16
  #undef op24
  #undef a8
  #undef x8

  strcat(s, t);
  strcat(s, " ");

  sprintf(t, "A:%.4x X:%.4x Y:%.4x S:%.4x D:%.4x DB:%.2x ",
    regs.a.w, regs.x.w, regs.y.w, regs.s.w, regs.d.w, regs.db);
  strcat(s, t);

  if(regs.e) {
    sprintf(t, "%c%c%c%c%c%c%c%c",
      regs.p.n ? 'N' : 'n', regs.p.v ? 'V' : 'v',
      regs.p.m ? '1' : '0', regs.p.x ? 'B' : 'b',
      regs.p.d ? 'D' : 'd', regs.p.i ? 'I' : 'i',
      regs.p.z ? 'Z' : 'z', regs.p.c ? 'C' : 'c');
  } else {
    sprintf(t, "%c%c%c%c%c%c%c%c",
      regs.p.n ? 'N' : 'n', regs.p.v ? 'V' : 'v',
      regs.p.m ? 'M' : 'm', regs.p.x ? 'X' : 'x',
      regs.p.d ? 'D' : 'd', regs.p.i ? 'I' : 'i',
      regs.p.z ? 'Z' : 'z', regs.p.c ? 'C' : 'c');
  }

  strcat(s, t);
  strcat(s, " ");

  sprintf(t, "V:%3d H:%4d", cpu.vcounter(), cpu.hcounter());
  strcat(s, t);
}

//opcode_length() retrieves the length of the next opcode
//to be executed. It is used by the debugger to step over,
//disable and proceed cpu opcodes.
//
//5 and 6 are special cases, 5 is used for #consts based on
//the A register size, 6 for the X/Y register size. the
//rest are literal sizes. There's no need to test for
//emulation mode, as regs.p.m/regs.p.x should *always* be
//set in emulation mode.

uint8 CPUcore::opcode_length() {
  uint8 op, len;
  static uint8 op_len_tbl[256] = {
  //0,1,2,3,  4,5,6,7,  8,9,a,b,  c,d,e,f

    2,2,2,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0x0n
    2,2,2,2,  2,2,2,2,  1,3,1,1,  3,3,3,4, //0x1n
    3,2,4,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0x2n
    2,2,2,2,  2,2,2,2,  1,3,1,1,  3,3,3,4, //0x3n

    1,2,2,2,  3,2,2,2,  1,5,1,1,  3,3,3,4, //0x4n
    2,2,2,2,  3,2,2,2,  1,3,1,1,  4,3,3,4, //0x5n
    1,2,3,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0x6n
    2,2,2,2,  2,2,2,2,  1,3,1,1,  3,3,3,4, //0x7n

    2,2,3,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0x8n
    2,2,2,2,  2,2,2,2,  1,3,1,1,  3,3,3,4, //0x9n
    6,2,6,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0xan
    2,2,2,2,  2,2,2,2,  1,3,1,1,  3,3,3,4, //0xbn

    6,2,2,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0xcn
    2,2,2,2,  2,2,2,2,  1,3,1,1,  3,3,3,4, //0xdn
    6,2,2,2,  2,2,2,2,  1,5,1,1,  3,3,3,4, //0xen
    2,2,2,2,  3,2,2,2,  1,3,1,1,  3,3,3,4  //0xfn
  };

  if(false /* in_opcode() == true */) {
    return 0;
  }

  op  = dreadb(regs.pc.d);
  len = op_len_tbl[op];
  if(len == 5) return (regs.e || regs.p.m) ? 2 : 3;
  if(len == 6) return (regs.e || regs.p.x) ? 2 : 3;
  return len;
}

#endif