JTAG_TAP status can't be exited shift_ir, and traped in loop

[Lebattt]

    // Set IR, but only if it needs to be set.
    task set_ir(input logic [IrLength-1:0] opcode);
      logic opcode_unpacked [IrLength];
      // check whether IR is already set to the right value
      if (this.ir_select == opcode) return;
      {<<{opcode_unpacked}} = opcode;
      write_tms(1); // select DR scan
      write_tms(1); // select IR scan
      write_tms(0); // capture IR
      write_tms(0); // shift IR
      write_bits(opcode_unpacked, 1);
      write_tms(1); // update IR
      write_tms(0); // run test idle
      this.ir_select = opcode;
    endtask

   // Assumes JTAG FSM is already in shift DR state
    task readwrite_bits(output logic rdata [$], input logic wdata [$], input logic tms_last);
      for (int i = 0; i < wdata.size(); i++) begin
        jtag.tdi <= #TA wdata[i];
        if (i == (wdata.size() - 1)) jtag.tms <= #TA tms_last; // tms_last ? exit1 DR : shift DR
        cycle_start();
        rdata[i] = jtag.tdo;
        cycle_end();
      end
      jtag.tms <= #TA 0; // tms_last ? pause DR : shift DR
    endtask

if execute jtag.tms <= #TA 0; // tms_last ? pause DR : shift DR , jtag_tap status changed to pause-ir, exit-2-ir, shift-ir, can't back to idle