oc8051_decoder.v

verilog code,about oc8051

          `OC8051_DJNZ_D : begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
            end
          `OC8051_RET : begin
              ram_rd_sel = `OC8051_RRS_SP;
              pc_wr = `OC8051_PCW_Y;
              pc_sel = `OC8051_PIS_AH;
            end
          `OC8051_RETI : begin
              ram_rd_sel = `OC8051_RRS_SP;
              pc_wr = `OC8051_PCW_Y;
              pc_sel = `OC8051_PIS_AH;
            end
          `OC8051_DIV : begin
              ram_rd_sel = `OC8051_RRS_B;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
            end
          `OC8051_MUL : begin
              ram_rd_sel = `OC8051_RRS_B;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
            end
         default begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
          end
        endcase
        comp_sel =  `OC8051_CSS_DC;
        rmw = `OC8051_RMW_N;
        stb_i = 1'b1;
        bit_addr = 1'b0;
      end
      2'b00: begin
        casex (op_cur) /* synopsys parallel_case */
          `OC8051_ACALL :begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_Y;
              pc_sel = `OC8051_PIS_I11;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_AJMP : begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_Y;
              pc_sel = `OC8051_PIS_I11;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_ADD_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ADDC_R : begin
             ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ANL_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_CJNE_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_DEC_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_DJNZ_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_INC_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOV_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOV_DR : begin
              ram_rd_sel = `OC8051_RRS_D;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOV_RD : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ORL_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_SUBB_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_XCH_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_XRL_R : begin
              ram_rd_sel = `OC8051_RRS_RN;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
    
    //op_code [7:1]
          `OC8051_ADD_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ADDC_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ANL_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_CJNE_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_DEC_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_INC_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOV_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOV_ID : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOV_DI : begin
              ram_rd_sel = `OC8051_RRS_D;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_MOVX_IA : begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_MOVX_AI :begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b0;
              bit_addr = 1'b0;
            end
          `OC8051_ORL_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_SUBB_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_XCH_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_XCHD :begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_XRL_I : begin
              ram_rd_sel = `OC8051_RRS_I;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
    
    //op_code [7:0]
          `OC8051_ADD_D : begin
              ram_rd_sel = `OC8051_RRS_D;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ADDC_D : begin
              ram_rd_sel = `OC8051_RRS_D;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_N;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ANL_D : begin
              ram_rd_sel = `OC8051_RRS_D;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ANL_C : begin
              ram_rd_sel = `OC8051_RRS_DC;
              pc_wr = `OC8051_PCW_N;
              pc_sel = `OC8051_PIS_DC;
              comp_sel =  `OC8051_CSS_DC;
              rmw = `OC8051_RMW_Y;
              stb_i = 1'b1;
              bit_addr = 1'b0;
            end
          `OC8051_ANL_DD : begin