//_mem[] is a uint8_t[] for RAM allocation
//_pMem is a moveable pointer to _mem[]
//NextByte() retreives the next byte from EEPROM

//Before this is if-else statements catching ranges of similar op codes
  ...
//This one catches similar math functions (mem op= num1):
  } else if (op >= 0x20 || op <= 0x2F) {
    uint8_t num1 = _mem[NextByte()];
    if      (op == 0x20) *_pMem += num1; //1A
    else if (op == 0x21) *_pMem -= num1; //1S

//For all other op codes:
  } else {

//These can mostly be ignored

    switch (op) {
      case 0x00: J(*_pMem);                                break; //J_
      case 0x01: _o = NextWord();                          break; //JA
      case 0x0A: ++_pMem;                                  break; //MI
      case 0x0B: --_pMem;                                  break; //MD
      case 0x0C: _pMem += NextByte();                      break; //MA
      case 0x0D: _pMem -= NextByte();                      break; //MS
      case 0x10: *_pMem = NextByte();                      break; //S_
      case 0x11: _mem[NextByte()] = _mem[NextByte()];      break; //CP
      case 0x12: *_pMem = _mem[NextByte()];                break; //V_
      case 0x13: _mem[NextByte()] = *_pMem;                break; //_V
      case 0x80: SV();                                     break; //SV
      case 0xFF: noHalt = false;                           break; //HT
    }

//the if-else statement for 0x20 and 0x21 is completely removed
      ...
      case 0x13: _mem[NextByte()] = *_pMem;                break; //_V
      case 0x20: *_pMem += _mem[NextByte()];               break; //1A
      case 0x21: *_pMem -= _mem[NextByte()];               break; //1S
      case 0x80: SV();                                     break; //SV
      ...