Controlling sequence library distibution

[Ilanr]

Hi All, 

 

I have a question about controlling sequence library distibution. I would like to give the test writer the ability to control sequences distribution. For that i am  using the uvm_sequence_library class. I saw that the index of a sequence in the library is determined by the order of sequence registration to the library (using `uvm_add_to_seq_lib macro). but this raises problem when removing sequences for example:

 

Project1 :

 

Sequence lib code:

constratint select_sequence_c { select_rand dist {   0:=20, // sequence_A

1:=100, // sequence_B

2:=20  // sequence_C

};}

 

The test owner would like to override the default distribution so in the test there is the following constraint layering:

constratint select_diff_dist { select_rand dist {  /*0:=20, // sequence_A*/

1:=30, // sequence_B

2:=30  // sequence_C

};}

 

Next project . Project2 does not include sequence A anymore so it was removed from the sequence library . Sequence index is now shifted.

 

constratint select_sequence_c { select_rand dist {  

0:=100, // sequence_B

1:=20  // sequence_C

};}

 

Now the test should be changed since index 1 does not point to sequence B anymore ( and so on…):

constratint select_diff_dist { select_rand dist {

1:=30, // sequence_B

2:=30  // sequence_C

};}

 

In OVM we used string based hash which is now deprecated:

constraint select_seq seq_kind dist {seq_kind dist Get_seq_kind(“sequence_A”) :=20,

seq_kind dist Get_seq_kind(“sequence_B”) :=20,

seq_kind dist Get_seq_kind(“sequence_C”) :=20};

}

 

 

Any idea how to solve this?

 

Thanks, 

Ilan

[uwes]

hi,

 

1.  set the      “selection_mode = UVM_SEQ_LIB_USER;  “ of the sequence library

2.  implement “virtual function int unsigned select_sequence(int unsigned max);” and return the index of the chosen sequence inside “sequences”

 

 

without having kind you could do something

 

begin

int item;

uvm_object_wrapper w[$] = {AS::get_type(),BS::get_type(),CS::get_type()};

void'(std::randomize(item) with {item dist {0:=20,1:=20,2:=20};});

 

// now just find the index of w[item] in sequences[$] and return it, or ...

 

end

 

/uwe