core/insn_alu_a.v

   1 `define INSN_alu_RLCA           3'b000
   2 `define INSN_alu_RRCA           3'b001
   3 `define INSN_alu_RLA            3'b010
   4 `define INSN_alu_RRA            3'b011
   5 `define INSN_alu_DAA            3'b100
   6 `define INSN_alu_CPL            3'b101
   7 `define INSN_alu_SCF            3'b110
   8 `define INSN_alu_CCF            3'b111
   9
  10 `define INSN_ALU_A              9'b000xxx111
  11
  12 `ifdef EXECUTE
  13         `INSN_ALU_A: begin
  14                 `EXEC_NEWCYCLE
  15                 `EXEC_INC_PC
  16         end
  17 `endif
  18
  19 `ifdef WRITEBACK
  20         `INSN_ALU_A: begin
  21                 case(opcode[5:3])
  22                 `INSN_alu_RLCA: begin
  23                         `_A <= {`_A[6:0],`_A[7]};
  24                         `_F <= {`_F[7:5],`_A[7],`_F[3:0]};
  25                 end
  26                 `INSN_alu_RRCA: begin
  27                         `_A <= {`_A[0],`_A[7:1]};
  28                         `_F <= {`_F[7:5],`_A[0],`_F[3:0]};
  29                 end
  30                 `INSN_alu_RLA: begin
  31                         `_A <= {`_A[6:0],`_F[4]};
  32                         `_F <= {`_F[7:5],`_A[7],`_F[3:0]};
  33                 end
  34                 `INSN_alu_RRA: begin
  35                         `_A <= {`_F[4],`_A[7:1]};
  36                         `_F <= {`_F[7:5],`_A[0],`_F[3:0]};
  37                 end
  38                 `INSN_alu_DAA: begin
  39                         if (`_F[6]) begin
  40                                 if (`_F[4]) begin
  41                                         if(`_A[3:0] >= 4'h6 && `_A[7:4] >= 4'h6 && `_F[5]) begin
  42                                                 `_A <= `_A + 8'h9A;
  43                                                 `_F <= {((`_A + 8'h9A) == 8'b0), `_F[6:0]};
  44                                         end
  45                                         else begin
  46                                                 `_A <= `_A + 8'hA0;
  47                                                 `_F <= {((`_A + 8'hA0) == 8'b0), `_F[6:0]};
  48                                         end
  49                                 end
  50                                 else begin
  51                                         if(`_A[3:0] <= 4'h9 && `_A[7:4] <= 4'h9 && !`_F[5]) begin
  52                                                 `_F <= {(`_A == 8'b0), `_F[6:0]};
  53                                         end
  54                                         else begin
  55                                                 `_A <= `_A + 8'hFA;
  56                                                 `_F <= {((`_A + 8'hFA) == 8'b0), `_F[6:0]};
  57                                         end
  58                                 end
  59                         end
  60                         else begin
  61                                 if (`_F[4]) begin
  62                                         if(`_F[5]) begin
  63                                                 `_A <= `_A + 8'h66;
  64                                                 `_F <= {((`_A + 8'h66) == 8'b0), `_F[6:0]};
  65                                         end
  66                                         else if (`_A[3:0] > 4'h9) begin
  67                                                 `_A <= `_A + 8'h66;
  68                                                 `_F <= {((`_A + 8'h66) == 8'b0), `_F[6:0]};
  69                                         end
  70                                         else begin
  71                                                 `_A <= `_A + 8'h60;
  72                                                 `_F <= {((`_A + 8'h60) == 8'b0), `_F[6:0]};
  73                                         end
  74                                 end
  75                                 else begin
  76                                         if(`_F[5]) begin
  77                                                 if(`_A[7:4] > 4'h9) begin
  78                                                         `_A <= `_A + 8'h66;
  79                                                         `_F <= {((`_A + 8'h66) == 8'b0), `_F[6:5], 1'b1, `_F[3:0]};
  80                                                 end
  81                                                 else begin
  82                                                         `_A <= `_A + 8'h06;
  83                                                         `_F <= {((`_A + 8'h06) == 8'b0), `_F[6:0]};
  84                                                 end
  85                                         end
  86                                         else begin
  87                                                 if(`_A[3:0] > 4'h9) begin
  88                                                         if (`_A[7:4] > 4'h8) begin
  89                                                                 `_A <= `_A + 8'h66;
  90                                                                 `_F <= {((`_A + 8'h66) == 8'b0), `_F[6:5], 1'b1, `_F[3:0]};
  91                                                         end
  92                                                         else begin
  93                                                                 `_A <= `_A + 8'h06;
  94                                                                 `_F <= {((`_A + 8'h06) == 8'b0), `_F[6:0]};
  95                                                         end
  96                                                 end
  97                                                 else begin
  98                                                         if (`_A[7:4] > 4'h9) begin
  99                                                                 `_A <= `_A + 8'h66;
 100                                                                 `_F <= {((`_A + 8'h66) == 8'b0), `_F[6:5], 1'b1, `_F[3:0]};
 101                                                         end
 102                                                         else begin
 103                                                                 `_F <= {(`_A == 8'b0), `_F[6:0]};
 104                                                         end
 105                                                 end
 106                                         end
 107                                 end
 108                         end
 109                 end
 110                 `INSN_alu_CPL: begin
 111                         `_A <= ~`_A;
 112                         `_F <= {`_F[7],1'b1,1'b1,`_F[4:0]};
 113                 end
 114                 `INSN_alu_SCF: begin
 115                         `_F <= {`_F[7:5],1'b1,`_F[3:0]};
 116                 end
 117                 `INSN_alu_CCF: begin
 118                         `_F <= {`_F[7:5],~`_F[4],`_F[3:0]};
 119                 end
 120                 endcase
 121         end
 122 `endif