Segmentation fault using DPI

[johannes.walter]

Hey!

I'm about to implement some register tests. So first of all I wanted to run all the UVM built-in test sequences.

But when I run the uvm_reg_access_seq I get the following error in QuestaSim:

** Fatal: (SIGSEGV) Bad handle or reference.
Time: 1531 ns  Iteration: 0  Process: /uvm_pkg::uvm_sequence_base::start/#FORK#285_2a96f3307 File: /opt/questasim_10.0b/questasim/verilog_src/uvm-1.0p1/src/dpi/uvm_hdl.svh
Fatal error in Module uvm_pkg at /opt/questasim_10.0b/questasim/verilog_src/uvm-1.0p1/src/dpi/uvm_hdl.svh line 121

I had a look at uvm_hdl.svh, line 121. It imports a C function from uvm_hdl.c which I cannot debug.

Has anyone an idea how I could fix this?

Regards,

Johannes

Edited July 26, 2011 by johannes.walter

[johannes.walter]

Okay. I did some more debugging.

I forgot to mention that my DUT is written in VHDL. So I would like to access some VHDL std_ulogics and std_ulogic_vectors using the UVM backdoor.

So here is what I found out:

The function "uvm_hdl_get_vlog" in uvm_hdl.c works well when I am trying to access a std_ulogic register. But the segmentation fault occurs when I try to get access to the value auf a std_ulogic_vector register.

Seems like the DPI/VPI extension cannot handle VHDL std_ulogic_vectors.

Has anyone had such a problem before?

Regards,

Johannes

[johannes.walter]

Hey!

The segmentation fault has gone away. I had to add the range of the std_ulogic_vector to the HDL path.

adc_conf_reg.add_hdl_path('{ '{"sfr_adc_conf_reg_s[6:0]", -1, -1} });

... did the trick.

But now I have got another error.

The uvm_hdl.c function tries to access each bit of the vector indiviually. But QuestaSim cannot find these paths.

Here is the error:

# UVM_ERROR: get: unable to locate hdl path top.dut.sfr_adc_conf_reg_s[0]
#  Either the name is incorrect, or you may not have PLI/ACC visibility to that name

What am I doing wrong? I also compiled every source file with +acc=rnb.

Regards,

Johannes

[johannes.walter]

This problem disappeared during development ... but now there is another one with accessing std_ulogic_vectors using the DPI/VPI.

I will open another thread for this:

http://www.uvmworld.org/forums/showthread.php?327-Valid-HDL-path-using-DPI-VPI-to-access-std_ulogic_vectors

Regards

Edited July 27, 2011 by johannes.walter