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Multidimensional array

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sresam89

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hello all
can somebody help in accessing and manipulating multidimensional array in vhdl.
any help will be lot appreciated as am finiding it difficult to manipulate the values in my 2 dimensional array as declared

type arr is array (6 downto 0) of std_logic_vector(6 downto 0);
signal and_1:arr;

when i can store values to the array why cant i read them or assign them a variable of same type?

thanks in advance
 

you can access them via:

and_1(3) <= "0010010";
and_1 <= (others => (others => '0'));

or something like that.

Please post your code.
 

i can store values using the following loop

for i in 0 to 3 loop
for j in 0 to 3 loop
and_1(i,j)<=(x(i) and y(j));
end loop;
end loop;

while i cant retrieve the values using

temp<=and_1(i,(j downto 0));

why is that?
 

what you talked about in your origional post, and your new post, are different things.

What you posted:
type arr is array (6 downto 0) of std_logic_vector(6 downto 0);

is not a 2D array. It is a 1d array of a 1d array type. This you can access with:

my_array(a)(b).

But what you can also do is access ranges. You can only access ranges in 1d arrays:

output <= my_array(a)(3 downto 0);

in your next post, you have a 2d array:
type arr is arrray(natural range<>, natural range <>) of integer;

which you access like this:

output <= my_array(i,j);

Each dimension is separated with a comma. You cannot access ranges inside the index, every element has to be accessed individuall, so (j downto 0) is illegal here.

what you will have to do is:

for k in j downto 0 loop
temp(k) <= and_1(i, k);
end loop;
 
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    j_andr

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vipinlal said:
Try

temp<=and_1(i)(j downto 0);
Click to expand...

that will be only valid if the array declaration was lyk

type arr is array (6 downto 0) of std_logic_vector(6 downto 0);
signal and_1:arr;

but then for that too if i use temp<=and_1(i)(j downto 0);
the temp variable is not getting any values during program run

---------- Post added at 16:07 ---------- Previous post was at 15:53 ----------
TrickyDicky said:
what you talked about in your origional post, and your new post, are different things.

What you posted:
type arr is array (6 downto 0) of std_logic_vector(6 downto 0);

is not a 2D array. It is a 1d array of a 1d array type. This you can access with:

my_array(a)(b).

But what you can also do is access ranges. You can only access ranges in 1d arrays:

output <= my_array(a)(3 downto 0);

in your next post, you have a 2d array:
type arr is arrray(natural range<>, natural range <>) of integer;

which you access like this:

output <= my_array(i,j);

Each dimension is separated with a comma. You cannot access ranges inside the index, every element has to be accessed individuall, so (j downto 0) is illegal here.

what you will have to do is:

for k in j downto 0 loop
temp(k) <= and_1(i, k);
end loop;
Click to expand...

sorry that i confused a bit

when i use

type arr is array (6 downto 0,6 downto 0) of std_logic;
signal and_1:arr;

i use

and_1(i,j)<=(x(i) and y(j));//to store values to 2d array
temp(j)<=and_1(i,j);//to retrieve value.

and while using

type arr is array (6 downto 0) of std_logic_vector(6 downto 0);
signal and_1:arr;

i use

and_1(i)(j)<=(x(i) and y(j));//to store values
temp<=and_1(i)(j);//to retrieve values

on both times am able to store values to array perfectly but unable retrieve them back

---------- Post added at 16:22 ---------- Previous post was at 16:07 ----------
TrickyDicky said:
output <= my_array(i,j);
[/QUOTE=TrickyDicky;940491]

what should be the type of output where u mentioned
Click to expand...
 

whatever the base type of the array is. In your case, probably std_logic.

I really suggest you do NOT create arrays of std_logic. It makes things annoying.
 

TrickyDicky said:
whatever the base type of the array is. In your case, probably std_logic.

I really suggest you do NOT create arrays of std_logic. It makes things annoying.
Click to expand...

i know its killing my time.still i need a piece of a code to retrieve the array values as mentioned above
please advice...

thanks.. in advance..
 

Code: 
for k in j downto 0 loop
  output(k) <= and_1(i, k);
end loop;

or if its not inside a process, use a generate loop
 

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