Re: [myhdl-list] AttributeError in 0.8-dev but not in 0.7

[Christopher F. <chr...@gm...>]

On 1/24/2013 5:49 AM, Per Karlsson wrote:
> Hi!
> I have dug a little deeper, and it has to do with using Signal(bool(False))
> and Signal(intbv(0)[1:0]).
> If I use only the latter and make all comparisons explicit ("if flag==1"
> instead of just "if flag") the AttributeError goes away.
> I have also seen that even if I don't get the attribute error there are
> simulation mismatches between the verilog and the myhdl when intbv and bool
> are mixed.
>
> I've seen this discussed on the boards before, and I think it is obvious
> that we need to support "if not flag:"-like syntax. It makes the code
> easier to read, and it works in both python and verilog.
> /Per
>

Thanks for the additional information but I still can't
reproduce the error with 0.8-dev (ignoring conversion
for now).  If I understand correctly you are saying if
you use /if Signal(intbv):/ and /if not Signal(intbv):/
it should cause the problem?

The following little test, works:

     def test():
         #flag = Signal(bool(0))
         flag = Signal(intbv(0)[1:])
         @instance
         def tb_stim():
             print('myhdl version %s' % (myhdl.__version__))
             print('start ...')
             for ii in range(3):
                 if not flag:
                     flag.next = not flag
                 yield delay(10)
                 print("%8d : %s" % (now(), repr(flag)))
                 if flag:
                     flag.next = not flag
                 yield delay(10)
                 print("%8d : %s" % (now(), repr(flag)))
             print('... end')

         return tb_stim

produces:
     >>> Simulation(test()).run()
     myhdl version 0.8dev
     start ...
           10 : Signal(intbv(True))
           20 : Signal(intbv(False))
           30 : Signal(intbv(True))
           40 : Signal(intbv(False))
           50 : Signal(intbv(True))
           60 : Signal(intbv(False))
     ... end

And I ran the same test with /flag = Signal(bool)/ and I
did not observe an issue either?

Regards,
Chris Felton