In reply to Er. Shipra:
For me it is totally unclear in which tasks/function you are doing what.
Does this code belong to your run_task in the driver?
@(posedge vif.aclk);
addr=ADDR_Q.pop_back;
strg.mem[addr]=dwdataQ1[j];
if(cfg.master_slave_select == AXI_SLAVE)
begin
for(int i=0;i<=tx.rlen;i++)
begin
@(posedge vif.aclk);
$display("\tQueue_1 size in read data is %0d",RADDR_Q.size());
addrr=RADDR_Q.pop_back();
if(strg.mem.exists(addrr))
$display("memory",mem);
vif.rdata<=strg.mem[addrr];