core/insn_add_hl.v

   1 `define INSN_ADD_HL             9'b000xx1001
   2
   3 `ifdef EXECUTE
   4         `INSN_ADD_HL: begin
   5                 case (cycle)
   6                 0:      case (opcode[5:4])
   7                         `INSN_reg16_BC: {tmp,tmp2} <= `_BC;
   8                         `INSN_reg16_DE: {tmp,tmp2} <= `_DE;
   9                         `INSN_reg16_HL: {tmp,tmp2} <= `_HL;
  10                         `INSN_reg16_SP: {tmp,tmp2} <= `_SP;
  11                         endcase
  12                 1:      begin
  13                                 `EXEC_INC_PC
  14                                 `EXEC_NEWCYCLE
  15                         end
  16                 endcase
  17         end
  18 `endif
  19
  20 `ifdef WRITEBACK
  21         `INSN_ADD_HL: begin
  22                 case (cycle)
  23                 0:      {tmp,tmp2} <= `_HL + {tmp,tmp2};
  24                 1:      begin
  25                                 `_F <=  { /* Z */ `_F[7],
  26                                           /* N */ 1'b0,
  27                                           /* H */ (({`_HL} + {tmp,tmp2}) & 16'h1000) ? 1'b1 : 1'b0,
  28                                           /* C */ (({1'b0,`_HL} + {1'b0,tmp,tmp2}) >> 16 == 1) ? 1'b1 : 1'b0,
  29                                           `_F[3:0]
  30                                         };
  31                                 `_HL <= {tmp, tmp2};
  32                         end
  33                 endcase
  34         end
  35 `endif