Constraint in uvm sequence

UVM
1

Hi
I have a problem in constraint in sequence
my constraint is

(1) If TXC is all zeroes:

64 bit TXD should be a multiple of 3 and 4, and TXD cannot contain

64’h06_06_06_06_06_06_06_06 or 64’h07_07_07_07_07_07_07_07

(2) If any bit of TXC[7:0] is 1, possible values of TXD are :

64’h06_06_06_06_06_06_06_06 or 64’h07_07_07_07_07_07_07_07

(3)The number of blocks sent from sequence should be even

txc and txd is input

my sequence class

class base_seq extends uvm_sequence#(seq_item);
seq_item tx;
`uvm_object_utils(base_seq)

function new(string name=“base_seq”);
super.new(name);
endfunction

task body();
repeat(60) begin
tx=seq_item::type_id::create(“tx”);
start_item(tx);

     assert(tx.randomize() with {(txc==8'h00)->(txd%3==0)||(txd%4==0)&&(txd!=64'h06_06_06_06_06_06_06_06 ||  64'h07_07_07_07_07_07_07_07);
 (txc== 8'hff|| 8'h01||8'hf1||8'hfe|| 8'hfc|| 8'hf8|| 8'he0||8'hc0|| 8'h80)->(txd==64'h06_06_06_06_06_06_06_06 ||  64'h07_07_07_07_07_07_07_07 );});


   finish_item(tx);       
  end
 endtask

endclass

I have done this but its not working and how to put 3rd condition in constraint
2

In reply to taufeeq_khan:
edaplayground code link

3

In reply to taufeeq_khan:

Waht do you mean with
(3)The number of blocks sent from sequence should be even.
Is it the number of seq_items?

4

In reply to chr_sue:

yes number of seqitem sent by the sequence should be even

5

In reply to taufeeq_khan:

class base_seq extends uvm_sequence#(seq_item);
  ...
  task body();
    rand int noitems;

    repeat(noitems) begin
      tx=seq_item::type_id::create("tx");
      start_item(tx);
      .....
      finish_item(tx);
    end
  endtask
endclass

In the sequence where you where you are starting your base_seq:

class my_sequence extends uvm_sequence(seq_item);
  ....
  task body ();
    base_seq my_seq;
    my_seq = base_seq::type_id::create("my_seq");
    assert(my_seq.randomize() with {noitems%2;});
    my_seq.start.seqr(): 
  endtask
endclass

Or you can do it alternatively in the run_phase of your test.
See the running code here: