init

code/vezba10/verif/Agent/calc_seq_item.sv

@@ -0,0 +1,120 @@
+`ifndef CALC_SEQ_ITEM_SV
+ `define CALC_SEQ_ITEM_SV
+
+parameter DATA_WIDTH  = 32;
+parameter RESP_WIDTH  = 2;
+parameter CMD_WIDTH   = 4;
+parameter NUM_PORTS   = 4;
+// Max clock cycles to wait for a response before declaring the request lost.
+// A correct Calc1 answers in a handful of cycles; the timeout only fires on a
+// DUT that never responds, so the environment reports an error instead of
+// hanging forever.
+parameter RSP_TIMEOUT = 64;
+
+//-----------------------------------------------------------------------------
+// Calc1 command encoding (see Vezba 5, Tabela 6).  All other 4-bit values are
+// treated by the design as "invalid" commands.
+//-----------------------------------------------------------------------------
+typedef enum bit [CMD_WIDTH-1:0] {
+   CMD_NOP = 4'b0000, // no operation
+   CMD_ADD = 4'b0001, // result = op1 + op2
+   CMD_SUB = 4'b0010, // result = op1 - op2
+   CMD_SHL = 4'b0101, // result = op1 << op2[4:0]
+   CMD_SHR = 4'b0110  // result = op1 >> op2[4:0]
+} calc_cmd_e;
+
+//-----------------------------------------------------------------------------
+// Calc1 response encoding (see Vezba 5, Tabela 8).
+//-----------------------------------------------------------------------------
+typedef enum bit [RESP_WIDTH-1:0] {
+   RESP_NONE    = 2'b00, // no response this cycle
+   RESP_SUCCESS = 2'b01, // operation successful, data on out_dataX
+   RESP_ERROR   = 2'b10  // overflow / underflow / invalid command
+   // 2'b11 is unused
+} calc_resp_e;
+
+//-----------------------------------------------------------------------------
+// Sequence item / transaction.
+//   - Stimulus (rand)     : port, cmd, op1, op2, delay
+//   - Observed (non-rand) : resp, result   (filled in by the monitor)
+//-----------------------------------------------------------------------------
+class calc_seq_item extends uvm_sequence_item;
+
+   // --- stimulus fields ---------------------------------------------------
+   rand bit [1:0]              port;   // target port 0..3  (-> req1..req4)
+   rand bit [CMD_WIDTH-1:0]    cmd;    // raw 4-bit command (allows invalid)
+   rand bit [DATA_WIDTH-1:0]   op1;    // operand 1
+   rand bit [DATA_WIDTH-1:0]   op2;    // operand 2
+   rand int unsigned           delay;  // idle cycles before issuing the request
+
+   // --- observed fields (driven by the monitor) ---------------------------
+   bit [RESP_WIDTH-1:0]        resp;   // observed out_respX
+   bit [DATA_WIDTH-1:0]        result; // observed out_dataX
+
+   // --- constraints --------------------------------------------------------
+   // A real request always carries a command; NOP would produce no response.
+   constraint c_no_nop  { cmd != CMD_NOP; }
+
+   // By default favour the four legal commands, but keep a small probability
+   // of an illegal command so the random regression exercises that path too.
+   constraint c_cmd_dist {
+      cmd dist {
+         CMD_ADD := 25,
+         CMD_SUB := 25,
+         CMD_SHL := 20,
+         CMD_SHR := 20,
+         [4'h3:4'h4] :/ 5,   // illegal
+         4'h7        :/ 5    // illegal
+      };
+   }
+
+   constraint c_delay { delay inside {[0:6]}; }
+
+   `uvm_object_utils_begin(calc_seq_item)
+      `uvm_field_int (port,   UVM_DEFAULT)
+      `uvm_field_int (cmd,    UVM_DEFAULT)
+      `uvm_field_int (op1,    UVM_DEFAULT)
+      `uvm_field_int (op2,    UVM_DEFAULT)
+      `uvm_field_int (delay,  UVM_DEFAULT | UVM_DEC)
+      `uvm_field_int (resp,   UVM_DEFAULT)
+      `uvm_field_int (result, UVM_DEFAULT)
+   `uvm_object_utils_end
+
+   function new (string name = "calc_seq_item");
+      super.new(name);
+   endfunction
+
+   // True when cmd is one of the four legal Calc1 commands.
+   function bit is_legal_cmd();
+      return (cmd inside {CMD_ADD, CMD_SUB, CMD_SHL, CMD_SHR});
+   endfunction
+
+   // Compact one-line description, handy in logs.
+   function string convert2string();
+      return $sformatf("port=%0d cmd=%s(0x%0h) op1=0x%08h op2=0x%08h -> resp=%s data=0x%08h",
+                       port+1, cmd2string(), cmd, op1, op2, resp2string(), result);
+   endfunction
+
+   function string cmd2string();
+      case (cmd)
+        CMD_NOP : return "NOP";
+        CMD_ADD : return "ADD";
+        CMD_SUB : return "SUB";
+        CMD_SHL : return "SHL";
+        CMD_SHR : return "SHR";
+        default : return "INVALID";
+      endcase
+   endfunction
+
+   function string resp2string();
+      case (resp)
+        RESP_NONE    : return "NONE";
+        RESP_SUCCESS : return "SUCCESS";
+        RESP_ERROR   : return "ERROR";
+        default      : return "RSVD";
+      endcase
+   endfunction
+
+endclass : calc_seq_item
+
+`endif