accessing bit in a Dynamic Array

[Deepu]

Hi All,

How can i access a bit in a dynamic array which is 16bit wide and
500000 depth

I tried as below:

reg [15:0] dynamic_array[];

// set the size
dynamic_array = new[500000];

// accessing a bit

num = 100000;

case(bit)
0: begin set = 1; dynamic_array[num][0] = 1; end
1: begin set = 1; dynamic_array[num][1] = 1; end
2: begin set = 1; dynamic_array[num][2] = 1; end
and so on till 15
14: begin set = 1; dynamic_array[num][3] = 1; end
15: begin set = 1; dynamic_array[num][4] = 1; end
endcase

But when i try to display it always gives 'x'. Is this a wrong way of
using? Is there any other better method if i have 'num' which is from
0 to 500000 and each num can have 16 bit value?

Thanks for the help!

 

[Jonathan Bromley]

On Wed, 2 Sep 2009 07:34:04 -0700 (PDT), Deepu wrote:

I tried as below:

reg [15:0] dynamic_array[];

// set the size
dynamic_array = new[500000];

// accessing a bit

num = 100000;

case(bit)
0: begin set = 1; dynamic_array[num][0] = 1; end
1: begin set = 1; dynamic_array[num][1] = 1; end
2: begin set = 1; dynamic_array[num][2] = 1; end
and so on till 15
14: begin set = 1; dynamic_array[num][3] = 1; end
15: begin set = 1; dynamic_array[num][4] = 1; end
endcase

But when i try to display it always gives 'x'.

I don't know what you mean by this.
Your code is illegal because "bit" is a SystemVerilog
keyword. Even if it were a variable name, I don't see
what your code is doing with that variable.


Here's the code I tried:

module da_bits;
reg [15:0] da[];
int num;
initial begin
da = new[500000];
num = 100000;
da[num][0] = 1;
$display("%b", da[num]);
$display("%b", da[num][0]);
end
endmodule

And the result I got was:

xxxxxxxxxxxxxxx1
1

Which, surely, is correct.

Is this a wrong way of using?

No, I don't think so. Maybe your display code is wrong?
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
jonathan.bromley@MYCOMPANY.com
http://www.MYCOMPANY.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.

 

[Jonathan Bromley]

On Wed, 2 Sep 2009 11:44:31 -0700 (PDT), Deepu wrote:

Can dynamic array be initialized inside the initial block?

initial
begin
for (i=0; i<500000; i=i+1)
begin
dynamic_array = 16'b0000000000000000;
end
end

Of course (but don't forget "new[]"!)
Why would you imagine it could not?

You may like this form even better:

initial begin
dynamic_array = new[500000];
foreach (dynamic_array)
dynamic_array = 0;
end

SystemVerilog may have its faults, but you
cannot criticise it for having too small
a collection of useful features
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
jonathan.bromley@MYCOMPANY.com
http://www.MYCOMPANY.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.

 

[Deepu]

Thanks for your input!!

Can dynamic array be initialized inside the initial block?

initial
begin
for (i=0; i<500000; i=i+1)
begin
dynamic_array = 16'b0000000000000000;
end
end

 

[parag]

On Sep 2, 7:34 pm, Deepu <pradeep...@gmail.com> wrote:

Hi All,

How can i access a bit in a dynamic array which is 16bit wide and
500000 depth

I tried as below:

reg [15:0] dynamic_array[];

// set the size
dynamic_array = new[500000];

// accessing a bit

num = 100000;

case(bit)
0: begin set = 1; dynamic_array[num][0] = 1; end
1: begin set = 1; dynamic_array[num][1] = 1; end
2: begin set = 1; dynamic_array[num][2] = 1; end
and so on till 15
14: begin set = 1; dynamic_array[num][3] = 1; end
15: begin set = 1; dynamic_array[num][4] = 1; end
endcase

But when i try to display it always gives 'x'. Is this  a wrong way of
using? Is there any other better method if i have 'num' which is from
0 to 500000 and each num can have 16 bit value?

Thanks for the help!

I have one doubt to ask
How did you compile the code,
since bit is a sv keyword
you seem to be getting till the point of display , that means it did
compile the code
can you name me the implementatino that you used
I mean whether you used VCS or some other compiler