predefined function/library

[Vincent]

Hello,

I tried to compile a vhdl file containing the function
addum(std_logic_vector,std_logic_vector)
Which library contain this function ?

thanks,

Vincent

 

[Egbert Molenkamp]

Vincent,

I know the function addum (ADD Unsigned Magnitued) from the Viewlogic
environment in the past.
If your design includes types like VLBIT, VLBIT_1D, indeed ViewLog BIT, you
probably need a package with the name pack1076.vhd to compile it in a VHDL
complaint environment.

With a google for "pack1976.vhd" I found this location
(http://www.inst.bnl.gov/~jack/htmls/behv/)
Be sure that NOT to use VHDL-1993 but use VHDL-1987. (This package is
already very old!).

This function addum used vlbit_1d (not std_logic_vector). It can be that
someone has used the same name but for type std_logic-vector.

Success,

Egbert Molenkamp

"Vincent" <vincent.bruyerenospam@nospam.enst-bretagne.fr> wrote in message
news:bjfrum$uur$1@news-reader3.wanadoo.fr...

Hello,

I tried to compile a vhdl file containing the function
addum(std_logic_vector,std_logic_vector)
Which library contain this function ?

thanks,

Vincent

 

[Vincent]

yes it is exactly what you mean !
it is used with types vlbit, vlbit_1d, ...
but it was said in the readme file it may be replaced by std_logic
so i replaced vlbit -> std_logic
vlbit_1d -> std_logic_vector
v1d2int( -> to_integer(unsigned(.
(the design is quite short, it is to design a PIC core)

but for the function, which one may i use to remplace addum, with the
std_logic library ?

Furthermore, i don't know if it was for the ViewLogic library but the
program use the following library :
-- library synth;
-- use synth.stdsynth.ALL;
i deleted it, is it useful ?

Thanks,

Vincent

"Egbert Molenkamp" <molenkam_remove_spam@cs.utwente.nl> a écrit dans le
message de news: bjhc6m$192$1@ares.cs.utwente.nl...

Vincent,

I know the function addum (ADD Unsigned Magnitued) from the Viewlogic
environment in the past.
If your design includes types like VLBIT, VLBIT_1D, indeed ViewLog BIT,
you
probably need a package with the name pack1076.vhd to compile it in a
VHDL
complaint environment.

With a google for "pack1976.vhd" I found this location
(http://www.inst.bnl.gov/~jack/htmls/behv/)
Be sure that NOT to use VHDL-1993 but use VHDL-1987. (This package is
already very old!).

This function addum used vlbit_1d (not std_logic_vector). It can be that
someone has used the same name but for type std_logic-vector.

Success,

Egbert Molenkamp

"Vincent" <vincent.bruyerenospam@nospam.enst-bretagne.fr> wrote in message
news:bjfrum$uur$1@news-reader3.wanadoo.fr...
Hello,

I tried to compile a vhdl file containing the function
addum(std_logic_vector,std_logic_vector)
Which library contain this function ?

thanks,

Vincent

 

[Egbert Molenkamp]

"Vincent" <vincent.bruyerenospam@nospam.enst-bretagne.fr> schreef in bericht
news:bjicsp$aa2$1@news-reader4.wanadoo.fr...

yes it is exactly what you mean !
it is used with types vlbit, vlbit_1d, ...
but it was said in the readme file it may be replaced by std_logic
so i replaced vlbit -> std_logic
vlbit_1d -> std_logic_vector
v1d2int( -> to_integer(unsigned(.

At that time, ~1990, most CAE tools had their own logical type. The VHDL
standard had type BIT and the users also wanted tri-state etc.
VLBIT is a four value logic ('X','0','1','Z'). It maybe that you can do the
suggetsed transformation in the package pack1076.vhd but I guess a synthesis
nowadays does not recognize that ADDUM is addition and will produce to
much/slow logic?

(the design is quite short, it is to design a PIC core)

but for the function, which one may i use to remplace addum, with the
std_logic library ?

Since it is short design would indeed consider change it in std_logic.
It is already clear that ADDUM performs an unsigned addition. So if the
vectors are added the shortes vector is zero-exented (the function ADD2C
performs a signed addition, in this the shortest vector in sign extended).
If you change your design I would suggest using the IEEE package NUMERIC_STD
(based on std_logic) (USE IEEE.NUMERIC_STD.ALL).
E.g.
variable a : unsigned (3 downto 0);
variable b,c : unsigned (5 downto 0);

c := a +b; performs the unsigned addition (due to the type 'unsigned').

Ok. the is the solution HOWEVER wait a moment .. If you add two vector you
may need an extra bit for the result! The function ADDUM generates a result
that is 1 bit longer then the longest vector (.e.g. in contrast to the "+"
form the package NUMERIC_STD (or STD_LOGIC_ARITH) ).
variable a : unsigned (3 downto 0);
variable b : unsigned (5 downto 0);
variable c : unsigned (6 downto 0);

c := ('0'&b) + a; -- behaviour of addum; extend the longest vector with
'0'.

However I remember that in most designs the extra bit was not needed. So
addum 'generated' it, and the user removed the extra bit. So maybe you can
simple perform an addition.

Furthermore, i don't know if it was for the ViewLogic library but the
program use the following library :
-- library synth;
-- use synth.stdsynth.ALL;
i deleted it, is it useful ?

Yes .. at that time. When I remember ViewLogic's synthesis tool needed it.
But indeed you can delete it now.

Egbert Molenkamp