Microprocessor memory

[Stefan Duenser]

Hello

I have implemented a very easy memory with a few registers, where i can
store and also read values for and from my ALU:

I have got 2 questions:

1) The conv_integer procedure does not work here, I always get the
errormessage: no feasable subprogram entry for conv_integer
2) Finally this memory should be synthizeable for a Xilinx ML300 board. What
do I have to change that this will be alright?
Is there a documention available? I wasnt able to find one online

Thanks for your help and time!

Cheers

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity memory is
generic (width : integer := 32);
port (clk : in std_ulogic;
rst : in std_ulogic;
inp : in std_ulogic_vector((2*width-1) downto 0);
addr: in std_ulogic_vector(3 downto 0);
wr : in std_ulogic;
rd : in std_ulogic;
outp: out std_ulogic_vector((2*width-1) downto 0)
);
end memory;

architecture rtl of memory is

type reg_type is array (0 to 3) of std_ulogic_vector((2*width-1) downto
0);
signal reg_file : reg_type;

begin

write : process(clk,rst,inp,addr,wr)
variable x_int : integer;
begin
if rst = '1' then
reg_file(0) <= (others => '0');
else
if clk'event and clk = '1' then
if wr = '1' then
reg_file(conv_integer(addr)) <= inp;
end if;
end if;
end if;
end process;

read : process(clk,rst,addr,rd)
begin
if rst = '1' then
outp <= (others => '0');
else
if clk'event and clk = '1' then
if rd = '1' then
outp <= reg_file(conv_integer(addr));
end if;
end if;
end if;
end process;

end rtl;

 

[Stefan Duenser]

1) The conv_integer procedure does not work here, I always get the

errormessage: no feasable subprogram entry for conv_integer. Any ideas
whats wrong here?

I really dont understand why this is not working, because this functions are
declared in the ieee.std_logic_arith.all header...

FUNCTION to_integer ( arg1 : STD_ULOGIC_VECTOR; x : INTEGER := 0 ) RETURN
INTEGER;
FUNCTION to_integer ( arg1 : STD_LOGIC_VECTOR; x : INTEGER := 0 ) RETURN
INTEGER;
FUNCTION to_integer ( arg1 : STD_LOGIC; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION to_integer ( arg1 : UNSIGNED; x : INTEGER := 0 ) RETURN NATURAL;
FUNCTION to_integer ( arg1 : SIGNED; x : INTEGER := 0 ) RETURN INTEGER;

FUNCTION conv_integer ( arg1 : STD_ULOGIC_VECTOR; x : INTEGER := 0 )
RETURN INTEGER;
FUNCTION conv_integer ( arg1 : STD_LOGIC_VECTOR; x : INTEGER := 0 )
RETURN INTEGER;
FUNCTION conv_integer ( arg1 : STD_LOGIC; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION conv_integer ( arg1 : UNSIGNED; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION conv_integer ( arg1 : SIGNED; x : INTEGER := 0 ) RETURN INTEGER

any useful tips?

 

[Egbert Molenkamp]

I really dont understand why this is not working, because this functions
are declared in the ieee.std_logic_arith.all header...

FUNCTION to_integer ( arg1 : STD_ULOGIC_VECTOR; x : INTEGER := 0 )
RETURN INTEGER;
FUNCTION to_integer ( arg1 : STD_LOGIC_VECTOR; x : INTEGER := 0 ) RETURN
INTEGER;
FUNCTION to_integer ( arg1 : STD_LOGIC; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION to_integer ( arg1 : UNSIGNED; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION to_integer ( arg1 : SIGNED; x : INTEGER := 0 ) RETURN INTEGER;

FUNCTION conv_integer ( arg1 : STD_ULOGIC_VECTOR; x : INTEGER := 0 )
RETURN INTEGER;
FUNCTION conv_integer ( arg1 : STD_LOGIC_VECTOR; x : INTEGER := 0 )
RETURN INTEGER;
FUNCTION conv_integer ( arg1 : STD_LOGIC; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION conv_integer ( arg1 : UNSIGNED; x : INTEGER := 0 ) RETURN
NATURAL;
FUNCTION conv_integer ( arg1 : SIGNED; x : INTEGER := 0 ) RETURN INTEGER

any useful tips?

If I have a look at the functions that are in your package std_logic_arith I
think that you are not using the Synopsys package std_logic_arith.
I can imagine you created your own package compiled it into library work and
use unintentionally the package that is in de library IEEE.

For the synopsys package you have to write: (notice the type conversion)
reg_file(conv_integer(std_logic_vector(addr))) <= inp;

Egbert Molenkamp

 

[Mike Treseler]

Try this.
-- Mike Treseler
------------------------------------------------------
-- Thu Jan 6 10:21:41 2005 register memory example
-- by Stefan Duenser cleaned up by Mike Treseler
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity memory is
generic (width : integer := 32);
port (clk : in std_ulogic;
rst : in std_ulogic;
inp : in std_ulogic_vector((2*width-1) downto 0);
addr : in std_ulogic_vector(3 downto 0);
wr : in std_ulogic;
rd : in std_ulogic;
outp : out std_ulogic_vector((2*width-1) downto 0)
);
end memory;

architecture rtl of memory is
type reg_type is array (0 to 3)
of std_ulogic_vector((2*width-1) downto 0);
signal reg_file : reg_type;
begin
one : process(clk, rst)
variable x_int : integer;
begin
if rst = '1' then
x_int := 0;
else
if clk'event and clk = '1' then
x_int := to_integer(unsigned(addr));
if wr = '1' then
reg_file(x_int) <= inp;
elsif rd = '1' then
outp <= reg_file(x_int);
end if;
end if;
end if;
end process one;
end rtl;

 

[Stefan Duenser]

Try this.

Thanks a lot Mike, it worked!! Also thanks for your hint Egbert!

Bye