Use the diamond operator to read the file/data. When a line starts with "//always" it triggers the begin of the block. You can use a Regular Expression to test this. Keep reading until you encounter an "//end" it's the end of the block. This should be straightforward.

Update

Something you can play with. You'll get the idea.

use strict;
use warnings;

while (my $line=<DATA>){
    if ($line =~ /\/\/always/){
        print "Start of block\n";
    }
    if ($line =~ /end\/\//) {
        print "End of block\n";    
    }
}

__DATA__
input [31:0]           ucast_mem_wdata;
   input [31:0]           ucast_mem_wren;
   input               ucast_mem_wr;
   input               ucast_mem_rd;
   output [31:0]           ucast_mem_rdata;

   wire [BMU_MEM_ADDR_BITS-1:0]   mem_addr; 
//always @ (posedge sys_clk or negedge sys_reset_n)
     begin
    if (!sys_reset_n)
      ucast_int_mem_rd_r <= 0;
    else
      ucast_int_mem_rd_r <= ucast_int_mem_rd & !ucast_access;
     end// this is the always block which i have to read into another 
+file
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