insn_ldm_a.v

   1 // If opcode[4], then ld A, x, else ld x, A
   2 // If opcode[1], then ld 16m8, else ld 8m8
   3
   4 `ifdef EXECUTE
   5         `INSN_LD8M_A,`INSN_LD16M_A: begin
   6                 case (cycle)
   7                 0:      begin
   8                                 `EXEC_INC_PC
   9                                 `EXEC_READ(`_PC + 16'h0001)
  10                         end
  11                 1:      begin
  12                                 `EXEC_INC_PC                    // we only hit here if 16m8
  13                                 `EXEC_READ(`_PC + 16'h0001)
  14                         end
  15                 2:      if (opcode[4])  // LD A,x
  16                                 `EXEC_READ(({tmp, tmp2}))
  17                         else
  18                                 `EXEC_WRITE(({tmp, tmp2}), `_A)
  19                 3:      begin
  20                                 `EXEC_NEWCYCLE
  21                                 `EXEC_INC_PC
  22                         end
  23                 endcase
  24         end
  25 `endif
  26
  27 `ifdef WRITEBACK
  28         `INSN_LD8M_A,`INSN_LD16M_A: begin
  29                 case (cycle)
  30                 0:      if (!opcode[1]) begin
  31                                 tmp <= 8'hFF;
  32                                 cycle <= 1;     /* Skip cycle 1 */
  33                         end
  34                 1:      tmp2 <= rdata;
  35                 2:      if (!opcode[1])
  36                                 tmp2 <= rdata;
  37                         else
  38                                 tmp <= rdata;
  39                 3:      if (opcode[4]) `_A <= rdata;
  40                 endcase
  41         end
  42 `endif
  43