Data width is 128 bits but only LSB 32-bits are valid

UVM
,
1

My AXI4 master and slave data width is 128 but each slave register size is of 32 bit.As per the design the lsb 32 bits of the data bus are valid. In my AXI4 vip the strobe is geting randomized. The valid attributes for are: Burst = FIxed , length = 0 , size = 32 bits.I forced Strobe to 16’000F But I am not getting write and read values from the registers same.
So how to make LSB 32 bits as valid.

2

just issue a write or read transfer of size 32bit by constraining AxSIZE to value 2. like say
constraint awsize_c {awsize <= 2;}
constraint arsize_c {arsize <= 2;}
Goal here is just to issue a transaction of size 32 bit only.

3

In reply to voraravi:

I would say it should be == rather than <= …


``` verilog

constraint awsize_c {awsize == 2;}
constraint arsize_c {arsize == 2;}
4

In reply to Subrahmanyam:

If your application wants narrow transfer, you can go with <= or if your application wants just 32 bit use ==.

5

Thank you for the suggestions. I have written this below .

module allign( input [127:0] axi_in_data,
                  input [15:0] in_strobe ,
                  output reg [15:0]out_strobe,
                  output reg [127:0] axi_out_data
                ) ;
  bit [7:0] temp [];
  typedef bit [31:0] a;
  bit [127:0] wdata;
  bit [127:0] wdata2;
  bit [31:0] wdata1;
  integer i,j;
  assign wdata = axi_in_data;
  assign axi_out_data = wdata2;
  assign out_strobe = 16'h000f;

  task automatic masking(bit [15:0] strobe);
    begin
    temp=new[4];
    j=0;
    for(i = 0; i<16; i=i+1) begin
      if(strobe[i]==1) begin
        temp[3-j] = wdata[8*i+:8];
        j=j+1;
      end
    end
    wdata1=a'(temp); // unpacked to packed array casting
    wdata2 = {96'h0,wdata1};
    end
  endtask

  always@(*) begin
    masking(in_strobe);
  end
 endmodule
6

In reply to voraravi:

According to DUT ,only LSB 32 bits are valid and I am using write and read API which will automatically set the AxSIZE = 3’b010.

7

In reply to krishna_:

Suggestion: use a queue array instead of a dynamic array.


task automatic masking(bit [15:0] strobe);
    for(i = 0; i<16; i=i+1) begin
       if(strobe[i]==1) begin
           temp.push_front(wdata[8*i+:8]);    //use push_front if you want to least significant
       end                                    //byte of wdata to be stored at higest index of
    end                                       //temp or else if least significant byte to be 
endtask                                       //stored at lower index of temp use push_back
8

In reply to voraravi:

Thank you for your suggestion sir. I will definitely consider queue inspite of an array.