use of is_relevant() in sequences

Hello Joseph,

You can do couple things; you can pre-generate the field of the do item or do item's field within is_relevant method, decide to start upon the generated value
pseudo code may look like

struct vr_pcie_tlp_pkt {
tlp_type: tlp_type_t;
tc: tc_t;
};

sequence vr_pcie_tl_seq {

!pre_tc: tc_t;

body()@driver.clock is {
do pkt keeping {
.tc == pre_tc;
};
};

is_relevant():bool is {
gen pre_tc;
return TRUE(tc in [0..3] and tc_pipe_is_empty);
};
};

Hi Levent, thanks for the recommendations. There's a major disadvantage that made us avoid the approaches you spoke of. That is, the user who is writing the sequences now has lost control of the field in terms of constraining as part of the do, or via extending the transaction item.

Joseph

Hi Joseph

Then your choice is always generate the item first.

The advantage of is relevant is to hold the generation till the last moment thus you can generate the item per the last snap shot of the environmet/dut status , because your generation may depend on the status. Forcv example, you hold of generation of a completion until there is an valid incoming request and generate the CMPL per specifics of that request.

Thus you need make a choice between
giving the same constraint control to user but not being able generate per the latest status
or
not giving the same constraint control

If you are OK with the first choice then (you may already do this)

extend FOO ex_atm_sequence {

// Items/subsequences
!cell: ex_atm_cell;

// The body() method
body() @driver.clock is {
var preprepared_cell: ex_atm_cell;
gen preprepared_cell;
...
//BLOCK until the condition is met
wait (prepared_cell.id == 5 and pipe_status==empty)
do cell keeping {it == preprepared_cell};
};

};


In this case user still can constraint the sequence or the "prepared_cell" item as he wishes. The down side is, as I mentioned, you loose the ability of generating the cell per the latest condition of environment/dut.

If still this wont resolve your issue please open up a service request and may be R&D experts can help you out

Cheers
Levent Caglar