title: ListLookUp in CHISEL
body: <p>I am new to Scala and I have been trying to understand the RISC-V architecture. I came across this piece of code, which I have been staring at for hours, unable to understand.</p>
  
  <pre><code>val csignals =                                                                                                   
    ListLookup(io.dat.inst,                                                                                       
                           List(N, BR_N  , OP1_X  ,  OP2_X  , ALU_X   , WB_X   , REN_0, MEN_0, M_X  , MT_X,  CSR.N),
             Array(       /* val  |  BR  |  op1   |   op2     |  ALU    |  wb  | rf   | mem  | mem  | mask |  csr  */
                          /* inst | type |   sel  |    sel    |   fcn   |  sel | wen  |  en  |  wr  | type |  cmd  */
                LW      -&gt; List(Y, BR_N  , OP1_RS1, OP2_IMI , ALU_ADD ,  WB_MEM, REN_1, MEN_1, M_XRD, MT_W,  CSR.N),
                LB      -&gt; List(Y, BR_N  , OP1_RS1, OP2_IMI , ALU_ADD ,  WB_MEM, REN_1, MEN_1, M_XRD, MT_B,  CSR.N),
                LBU     -&gt; List(Y, BR_N  , OP1_RS1, OP2_IMI , ALU_ADD ,  WB_MEM, REN_1, MEN_1, M_XRD, MT_BU, CSR.N),... 
  </code></pre>
  
  <ol>
  <li>What ListLookUp exactly does here ?</li>
  <li>Is the value of     'csignals' Boolean or something else ? </li>
  </ol>