5                         `INSN_reg16_BC: {tmp,tmp2} <= `_BC;
 
   6                         `INSN_reg16_DE: {tmp,tmp2} <= `_DE;
 
   7                         `INSN_reg16_HL: {tmp,tmp2} <= `_HL;
 
   8                         `INSN_reg16_SP: {tmp,tmp2} <= `_SP;
 
  21                 0:      {tmp,tmp2} <= {tmp,tmp2} +
 
  22                                 (opcode[3] ? 16'hFFFF : 16'h0001);
 
  24                         `INSN_reg16_BC: `_BC <= {tmp,tmp2};
 
  25                         `INSN_reg16_DE: `_DE <= {tmp,tmp2};
 
  26                         `INSN_reg16_HL: `_HL <= {tmp,tmp2};
 
  27                         `INSN_reg16_SP: `_SP <= {tmp,tmp2};