Re: [myhdl-list] Constant ints in interfaces

[SHEN C. <she...@co...>]

 

Hi Keerthan, 

I will write more cases as you said. So I hope folks
here will post exotic way of abusing interface, so we could clarifying
what are supported v.s. what are not. 

By doing this, we can have a
spec first, before anyone attempting a fix. 

For instance, do you think
it's a good idea to have a Interface base class, and requires all
interface to derive from the base class? 

With this convention, during
extractHier/analyze, we can unambiguously identify interface objects,
descend into it and extract its member signals. 

regards,
Shenchen 

On
2015-03-16 19:46, Keerthan JC wrote: 

> This is a bug, not a
limitation. Please post additional testcases to the issue I just
created. https://github.com/jandecaluwe/myhdl/issues/33 [10]
> 
> I will
look into this later this week.
> 
> On Mon, Mar 16, 2015 at 7:18 AM,
SHEN Chen <she...@co... [11]> wrote:
> 
>> Hi all,
>> 
>> I
encountered similar problem recently. This is a generic problem in
>>
the current implementation of interface.
>> 
>> In your code, the
following line is critical:
>> tiWIDTH_FPN = self.WIDTH_FPN
>> 
>> With
this line, Python creates a local variable named "tiWIDTH_FPN".
>> 
>>
In the previous versions of MyHDL, during conversion/elaboration, we
>>
put all local variables to "symdict".
>> I found two places where
symdict is constructed, in _extractHier and in
>> _analyzeGens:
>> -
>>
https://github.com/jandecaluwe/myhdl/blob/master/myhdl/_extractHierarchy.py#L317
[1]
>> -
>>
https://github.com/jandecaluwe/myhdl/blob/master/myhdl/conversion/_analyze.py#L149
[2]
>> 
>> Unfortunately, in the current implementation of interface, I
couldn't
>> find a place where self.WIDTH_FPN being added to symdict.
>>

>> I recently found that, if a signal isn't included in symdict, it
will
>> appear as constant in converted code.
>> This is the origin of
the remaining caveat I mentioned in pull request
>> 21
(https://github.com/jandecaluwe/myhdl/pull/21 [3]).
>> 
>> One
workaround is simply to create a local copy of all signals in the
>>
interface.
>> In my project, I even created an Interface base class, and
defined an
>> signals() member method, so in the logic generators I can
write:
>> tiWIDTH_FPN, tiWIDTH_PRNU = self.signals()
>> 
>>
Unfortunately, Python does not allow the following:
>> createLocalVars(
self.signals() )
>> so you will have to hand-write the left-hand-side of
the assignment, in
>> order to create local variables.
>> 
>>
regards,
>> shenchne
>> 
>> On 2015-03-16 18:03, Josy Boelen wrote:
>>

>> >> class Interface(object): def __init__(self): self.a =
>> >>
Signal(intbv(0,
>> >> min=-1000, max=1000)) self.c = 10 where c gets
converted as
>> >> interface_name.c. My understanding from the docs is
that this should
>> >> be
>> >> supported, but I might be missing
something. I noticed this
>> >> previously
>> >> with IntEnum,
>> >
>> >
but
>> >
>> 
>>> Henry,
>> >
>> > I noticed similar behaviour when using
a class (as I also have local
>> > functions in the class), here is my
code:
>> > class CorrectionCoefficients(object):
>> > ''' a VHDL-record
like object '''
>> > def __init__(self, WIDTH_PRNU, WIDTH_FPN, p = 0, f
= 0):
>> > self.WIDTH_FPN = WIDTH_FPN
>> > self.WIDTH_PRNU =
WIDTH_PRNU
>> > self.fpn = Signal(intbv(f)[WIDTH_FPN:])
>> > self.prnu =
Signal(intbv(p)[WIDTH_PRNU:])
>> >
>> > def
toCorrectionCoefficients(self, v):
>> > # need an unique name as 'alias'
otherwise the 'self.WIDTH_FPN'
>> > shows up as a constant in the
VHDL
>> > tccWIDTH_FPN = self.WIDTH_FPN
>> > @always_comb
>> > def
tcc():
>> > lv = v
>> > self.fpn.next = lv[tccWIDTH_FPN:]
>> >
self.prnu.next = lv[:tccWIDTH_FPN]
>> >
>> > return tcc
>> >
>> > def
tointbv(self, y):
>> > ''' build a flattened vector from the record's
elements in
>> > ascending order'''
>> > # need an unique name as
'alias' otherwise the 'self.WIDTH_FPN'
>> > shows up as a constant in
the VHDL :)
>> > tiWIDTH_FPN = self.WIDTH_FPN
>> >
>> > @always_comb
>>
> def ti():
>> > y.next[tiWIDTH_FPN:] = self.fpn
>> >
y.next[:tiWIDTH_FPN] = self.prnu
>> >
>> > return ti
>> >
>> >
Regards,
>> >
>> > Josy
>> >
>> >
>>
------------------------------------------------------------------------------
>>
> Dive into the World of Parallel Programming The Go Parallel
Website,
>> > sponsored
>> > by Intel and developed in partnership with
Slashdot Media, is your
>> > hub
>> > for all
>> > things parallel
software development, from weekly thought leadership
>> > blogs to
>> >
news, videos, case studies, tutorials and more. Take a look and join
>>
> the
>> > conversation now. http://goparallel.sourceforge.net/ [4]
>> >
_______________________________________________
>> > myhdl-list mailing
list
>> > myh...@li... [5]
>> >
https://lists.sourceforge.net/lists/listinfo/myhdl-list [6]
>> 
>>
------------------------------------------------------------------------------
>>
Dive into the World of Parallel Programming The Go Parallel Website,
sponsored
>> by Intel and developed in partnership with Slashdot Media,
is your hub for all
>> things parallel software development, from weekly
thought leadership blogs to
>> news, videos, case studies, tutorials and
more. Take a look and join the
>> conversation now.
http://goparallel.sourceforge.net/ [7]
>>
_______________________________________________
>> myhdl-list mailing
list
>> myh...@li... [8]
>>
https://lists.sourceforge.net/lists/listinfo/myhdl-list [9]
> 
> -- 
>

> have a nice day
> -jck

-- 

SHEN Chen General
Manager
---------------------------------
Cogenda Co Ltd
SISPARK II Room
C102-1, 1355 Jinjihu Avenue, Suzhou, Jiangsu, China
Phone(Fax): +86 512
67900636
Homepage: http://www.cogenda.com
 

Links:
------
[1]
https://github.com/jandecaluwe/myhdl/blob/master/myhdl/_extractHierarchy.py#L317
[2]
https://github.com/jandecaluwe/myhdl/blob/master/myhdl/conversion/_analyze.py#L149
[3]
https://github.com/jandecaluwe/myhdl/pull/21
[4]
http://goparallel.sourceforge.net/
[5]
mailto:myh...@li...
[6]
https://lists.sourceforge.net/lists/listinfo/myhdl-list
[7]
http://goparallel.sourceforge.net/
[8]
mailto:myh...@li...
[9]
https://lists.sourceforge.net/lists/listinfo/myhdl-list
[10]
https://github.com/jandecaluwe/myhdl/issues/33
[11]
mailto:she...@co...