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NULL pointer dereference

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Hi,

I am building an uVC using uRM in SVCB for the First time.
When I wanted to Access the Transaction item from the Driver using "get_next_item" predefined task(defined in urm_driver class library) it is generating an error as,

Error!  NULL pointer dereference
          File: /tools/cadence/ius/tools/urm/src/urm/sv/urm_unit.svh, line = 119, pos = 25
         Scope: top.urm_unit::m_get_message_handler
          Time: 20 NS + 1
Verilog Stack Trace:
0: function top.urm_unit::m_get_message_handler at /tools/cadence/ius/tools/urm/src/urm/sv/urm_unit.svh:119
1: task top.urm_driver::get_next_item at /tools/cadence/ius/tools/urm/src/uvc/sv/urm_driver.sv:546
2: task top.master_bfm@876_2.drive_transfers at   sv/master_bfm.sv:85
3: process in top.master_bfm::run at /sv/master_bfm.sv:58

Infact I am not Using any TLM ports as of now.
I am Puzzled by this error, I will be Thankful for the Suggestions.

Regards,
Ramesh Pal Yadav


Originally posted in cdnusers.org by ramesh_pal_yadav
Parents

  • Hi Ramesh,

    In the URM XBUS example, the xbus_master_driver is generating sequences - this is what I meant by "Sequencer" (which is the terminology used in the new OVM).

    The BFM (which is called a "driver" in OVM) gets sequence items e.g. by calling driver.get_next_item(seq_item). However, the driver variable must be initialised to point to the object generating the sequences (otherwise you will get a "NULL POINTER" error). In the XBUS example this is done in the build method of xbus_master_agent:

    bfm.driver = this.driver;

    You should have a similar statement in your code.

    My comment about configuring the sequencer is related to the set_*_override functions that can be called to determine what sequences are generated by the factory - see section 2.9 of the svcb user guide.

    Regards,
    Dave


    Originally posted in cdnusers.org by dl_doulos
Reply

  • Hi Ramesh,

    In the URM XBUS example, the xbus_master_driver is generating sequences - this is what I meant by "Sequencer" (which is the terminology used in the new OVM).

    The BFM (which is called a "driver" in OVM) gets sequence items e.g. by calling driver.get_next_item(seq_item). However, the driver variable must be initialised to point to the object generating the sequences (otherwise you will get a "NULL POINTER" error). In the XBUS example this is done in the build method of xbus_master_agent:

    bfm.driver = this.driver;

    You should have a similar statement in your code.

    My comment about configuring the sequencer is related to the set_*_override functions that can be called to determine what sequences are generated by the factory - see section 2.9 of the svcb user guide.

    Regards,
    Dave


    Originally posted in cdnusers.org by dl_doulos
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