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[SOLVED] Writing to an output file in VHDL

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M

MSAKARIM

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I'm trying to write some data to an output file in VHDL but i have this error during SIMULATION step :

" ** Failure: (vsim-4) ****** Memory allocation failure. *****
#
# Attempting to allocate 2147483664 bytes
#
# Please check your system for available memory and swap space.
# Time: 0 ps Iteration: 0 Process: /padtofile/line__30 "
Click to expand...

My code is:

Code VHDL - [expand]
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library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.NUMERIC_STD.All;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
USE IEEE.STD_LOGIC_TEXTIO.ALL;
USE STD.TEXTIO.ALL;
 
entity Padtofile is
generic(          block_size    :  integer      := 1024;    --bits
          length_bits   :  integer  := 128  );--bits
port(message: in std_logic_vector(63 downto 0));
end Padtofile;
 
 
architecture Behavioral of Padtofile is
signal clock,endoffile : bit := '0';
signal    linenumber : integer:=1; 
 
 
begin
clock <= not (clock) after 1 ns;   
 
 
process
variable mod_val: integer;
variable padding_length : integer;
variable padded_length : integer;
variable message_length: std_logic_vector((length_bits - 1) downto 0 ) := (others=>'0');
variable padded_message: std_logic_vector ((padded_length - 1) downto 0) := (others => '0');
Variable padding: std_logic_vector ((padding_length) downto 0) := (others => '0');
 
file      outfile  : text is out "Pad.txt";  --declare output file
variable  outline  : line;   --line number declaration  
begin
--padding message
mod_val:= (message'length) mod block_size;
padding_length := ((block_size-129)+(block_size - mod_val));
padded_length := ( message'length + (1 + padding_length) + length_bits);
message_length := std_logic_vector(to_unsigned(message'length,length_bits)); 
padding := "1" & std_logic_vector(to_unsigned(0,padding_length));  
padded_message := message & padding & message_length; 
 
 
wait until clock = '0' and clock'event;
if(endoffile='0') then  
 
write(outline, padded_message, right, block_size);
writeline(outfile, outline);
-- write line to external file.
 
linenumber <= linenumber + 1;
else
null;
end if;
 
end process;
 
end Behavioral;
 

variable padded_length : integer;
Variable padding: std_logic_vector ((padding_length) downto 0) := (others => '0');

Here is your problem
Edit----------
What probably happening is your computer is struggling to create the std_logic_vector padding, because it's such a mammoth size your local computer/software cannot create a register to capture that std_logic_vector
 
padding_length is an integer with no initial value. So will be set to -2^31+1 (same with padded_length). It means your message_length and padded_message and padding arrays have a 0 length (because they are null arrays). But this wont be the problem.
You're then trying to assign some very long stvs to these null arrays.

I also not you're using '87 style file declarations. The '93 declaration style is:

Code: 
file f: text open WRITE_MODE is "some_file.txt";

Im not really sure what you're trying to do
 
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