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Removed init.
Better over/underfill cover properties for verific.  Moved basic cover statement to only be used when there is no verific.

Other general tidy up.
Also updated/fixed a couple minor things in newstart.rst.
This commit is contained in:
KrystalDelusion 2022-08-02 12:11:09 +12:00
parent a76286ed34
commit cfa4352bae
3 changed files with 97 additions and 109 deletions
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13
docs/source/newstart.rst
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@ -131,7 +131,7 @@ adjustments to code and rerunning tests to validate.
sby -f fifo.sby nofullskip
The noskip task disables the code shown below. Because the count signal has
The nofullskip task disables the code shown below. Because the count signal has
been written such that it cannot exceed MAX_DATA, removing this code will lead
to the ``a_count_diff`` assertion failing. Without this assertion, there is no
guarantee that data will be read in the same order it was written should an
@ -143,13 +143,12 @@ overflow occur and the oldest data be written.
:end-at: endif
:lines: 1-5,9
The last few lines of output for the noskip task should be similar to the
The last few lines of output for the nofullskip task should be similar to the
following:
.. code-block:: text
SBY [fifo_nofullskip] engine_0.basecase: ## Assert failed in fifo: a_count_diff
SBY [fifo_nofullskip] engine_0.basecase: ## Assert failed in fifo: ap_underfill
SBY [fifo_nofullskip] engine_0.basecase: ## Writing trace to VCD file: engine_0/trace.vcd
SBY [fifo_nofullskip] engine_0.basecase: ## Writing trace to Verilog testbench: engine_0/trace_tb.v
SBY [fifo_nofullskip] engine_0.basecase: ## Writing trace to constraints file: engine_0/trace.smtc
@ -162,7 +161,7 @@ following:
SBY [fifo_nofullskip] summary: engine_0 (smtbmc boolector) returned FAIL for basecase
SBY [fifo_nofullskip] summary: counterexample trace: fifo_nofullskip/engine_0/trace.vcd
SBY [fifo_nofullskip] DONE (FAIL, rc=2)
SBY The following tasks failed: ['noskip']
SBY The following tasks failed: ['nofullskip']
Using the ``noskip.gtkw`` file provided, use the below command to examine the
error trace.
@ -189,16 +188,16 @@ Searching the file for ``w_underfill`` will reveal the below.
.. code-block:: text
$ grep "w_underfill" fifo_cover/logfile.txt -A 1
$ grep "w_underfill" fifo_cover/logfile.txt -A 2
SBY [fifo_cover] engine_0: ## Reached cover statement at w_underfill in step 2.
SBY [fifo_cover] engine_0: ## Writing trace to VCD file: engine_0/trace2.vcd
SBY [fifo_cover] engine_0: ## Writing trace to VCD file: engine_0/trace4.vcd
We can then run gtkwave with the trace file indicated to see the correct
operation as in the image below. When the buffer is empty, a read with no write
will result in the ``wksip`` signal going high, incrementing *both* read and
write addresses and avoiding underflow.
gtkwave fifo_cover/engine_0/trace2.vcd noskip.gtkw
gtkwave fifo_cover/engine_0/trace4.vcd noskip.gtkw
.. image:: media/gtkwave_coverskip.png