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Can we use $writememh in a for loop? I am trying to write to a file from different memories alternatively, and I am getting a warning:

Warning: More indices than needed

I have googled, but nothing is written about this warning. Below is the sample code:

reg [7:0] Mem_x[1023:0];
reg [7:0] Mem_y[1023:0];
reg [7:0] Mem_z[1023:0];
reg [31:0] image[1023:0];
initial
begin
#1000
for (l = 0; l < 25; l = l + 1)  
    @(posedge Clock)
     begin 
        $writememh("writefile_out.hex",Mem_x[l]);  
        $writememh("writefile_out.hex",Mem_y[l]); 
        $writememh("writefile_out.hex",Mem_z[l]);
        $writememh("writefile_out.hex",image[l][7:0]); 
I assume Mem_x, Mem_y, Mem_z and image are declared something like:
integer Mem_x[0:24];
integer Mem_y[0:24];
integer Mem_z[0:24];
reg [7:0] image[0:24];
In which case you want a file that reads something like:
{Mem_x[0]}
{Mem_y[0]}
{Mem_z[0]}
{image[0]}
{Mem_x[1]}
{Mem_y[1]}
{Mem_z[1]}
{image[1]}
{Mem_x[2]}
Where each of those in a hex value for the variable indicated.
If so, you cannot use $writememh to achieve this; because $writememh overwrites the given file, it does NOT append to it. So, with each call, you are erasing the previous contents of "writefile_out.hex". Also, the reason you are getting that error is because Mem_x[l] and the others are not arrays, they are elements of arrays and $writememh expects an array as an argument (thus, too many indexes error).
However, you can use $fdisplay to achieve what you want (and then some). Heres an example:
integer outfile;
integer i;
reg [7:0] mem1[0:9];
reg [7:0] mem2[0:9];
initial begin
  outfile = $fopen("out.hex");
  for (i = 0; i < 10; i = i + 1) begin
    $fdisplay(outfile, "%02x\n%02x\n", mem1[i], mem2[i]);
Using $fdisplay means you can format the output however you like, so it doesnt have to be constrained to the standard hex format used by $readmemh and $writememh, unless you want it to be, then you just use something like I have above.
        
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