core/insn_alu_ext.v

   1 `define INSN_ALU_EXT            9'b100xxxxxx
   2
   3 `ifdef EXECUTE
   4         `INSN_ALU_EXT: begin
   5                 if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0))
   6                         `EXEC_READ(`_HL)
   7                 else begin
   8                         `EXEC_INC_PC
   9                         case (opcode[2:0])
  10                         `INSN_reg_A:    tmp <= `_A;
  11                         `INSN_reg_B:    tmp <= `_B;
  12                         `INSN_reg_C:    tmp <= `_C;
  13                         `INSN_reg_D:    tmp <= `_D;
  14                         `INSN_reg_E:    tmp <= `_E;
  15                         `INSN_reg_H:    tmp <= `_H;
  16                         `INSN_reg_L:    tmp <= `_L;
  17                         `INSN_reg_dHL:  tmp <= rdata;
  18                         endcase
  19                 end
  20         end
  21 `endif
  22
  23 `ifdef WRITEBACK
  24         `INSN_ALU_EXT: begin
  25                 if (opcode[2:0] == `INSN_reg_dHL) begin
  26                         if(cycle == 0) begin end
  27                         else if(cycle == 1) begin
  28                                 `EXEC_WRITE(`_HL, alu_res)
  29                                 `_F <= {f_res,`_F[3:0]};
  30                         end else begin
  31                                 `EXEC_NEWCYCLE
  32                         end
  33                 end else begin
  34                         case(opcode[2:0])
  35                         `INSN_reg_B: `_B <= alu_res;
  36                         `INSN_reg_C: `_C <= alu_res;
  37                         `INSN_reg_D: `_D <= alu_res;
  38                         `INSN_reg_E: `_E <= alu_res;
  39                         `INSN_reg_H: `_H <= alu_res;
  40                         `INSN_reg_L: `_L <= alu_res;
  41                         `INSN_reg_A: `_A <= alu_res;
  42                         `INSN_reg_dHL: begin end /* eat dicks */
  43                         endcase
  44                         `_F <= {f_res,`_F[3:0]};
  45                         `EXEC_NEWCYCLE
  46                 end
  47         end
  48 `endif