Re: [myhdl-list] Restrictions for conversion (initial values)

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

<snip>
>> To get to an actual synthesizable approach it
>> appears the initial values would not be enough?
>
> The initial values for the array signal are enough for a synthesizable
> approach.
> The Function with is used in the VHDL code is just another way which can
> be used to give the
> signals in the array there initial values in a more procedural way (for
> vhdl). If you have the procedure
> wich gives the values in python, you can write the initial values in vhdl
> to the array directly.
> The "specifying initial memory contents at power-up"
>

Is this true for Verilog and VHDL?  And is it true across multiple 
vendor tools?  IMO the actual creation of the pre-init RAM is less 
important, unless widely advertised, than wide support of pre-init. 
Reworded, adding the init support even if it doesn't support pre-init 
RAM in the vendor synthesis is ok, IMO.

>
>> One of the reasons why initial values has not been implemented (it is on
>> the todo list,
>> http://www.myhdl.org/doku.php/dev:tasks#initial_values_suppot) is that
>> it was observed that Quartus did not support initial value support in
>> Verilog.  There would be a mis-match between the Verilog conversion and
>> VHDL conversion.
>
> I just can say that i use quartus v11.1 and i dont see this limitation
> there.
> But this is probably not satisfactorily if someone uses a older version.

I think moving forward that is ok, not to support older Quartus, I don't 
recall any objections in the past.

But to clarify, you do not see initial value errors with Verilog in Quartus?

>
> There is this another open task:
> http://www.myhdl.org/doku.php/dev:tasks # More general support of indexed
> constants
>
> If the  array of signals is initialized with values (also in the vhdl an
> verilig code)
>    you can then use it also as a indexed "constant" value
> in a more general way, this signal can  be used everyvere where like a
> normal signal.
> if you never write to this signal it is just like a constant.
>
>
> greetings
> Norbo
>
>
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