urv: add MIMPID.

rtl/urv_csr.v

@@ -88,6 +88,7 @@ module urv_csr
        `CSR_ID_MIP: csr_in1 <= csr_mip_i;
        `CSR_ID_MIE: csr_in1 <= csr_mie_i;
        `CSR_ID_DBGMBX: csr_in1 <= g_with_hw_debug ? mbx_data : 32'h0;
+       `CSR_ID_MIMPID: csr_in1 <= 32'h20190125;
        default: csr_in1 <= 32'h0;
      endcase // case (d_csr_sel_i)
 

rtl/urv_defs.v

@@ -88,6 +88,12 @@
 `define CSR_ID_MIP 12'h344
 `define CSR_ID_MIE 12'h304
 `define CSR_ID_DBGMBX 12'h7d0
+`define CSR_ID_MIMPID 12'hf13
+
+/* History for MIMPID:
+   0000_0000: mimpid not implemented
+   2019_0125: mimpid added.
+*/
 
 `define CSR_OP_CSRRW 3'b001
 `define CSR_OP_CSRRS 3'b010