Subversion Repositories qaz_libs

//////////////////////////////////////////////////////////////////////
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//// Copyright (C) 2018 Authors and OPENCORES.ORG                 ////
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//// This source file is free software; you can redistribute it   ////
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//////////////////////////////////////////////////////////////////////


// --------------------------------------------------------------------
 typedef enum
 {
    NONE,
    SPORADIC,
    // BURSTY,
    REGULAR
 } random_delay_type_e;

// --------------------------------------------------------------------
class random_delay;

  rand int unsigned delay = 0;
  time wait_timescale = 1ns;

  // --------------------------------------------------------------------
  virtual function void set_delay(random_delay_type_e kind = REGULAR);
    case(kind)
      NONE:     delay = 0;
      SPORADIC: assert(this.randomize() with{delay dist {0 := 96, [1:3] := 3, [4:7] := 1};});
      REGULAR:  assert(this.randomize() with{delay dist {0 := 60, [1:3] := 30, [4:7] := 10};});
      default:  delay = 0;
    endcase
  endfunction: set_delay

  // --------------------------------------------------------------------
  virtual task next(random_delay_type_e kind = REGULAR);
    set_delay(kind);
    #(delay * wait_timescale);
  endtask: next

  // --------------------------------------------------------------------
  virtual function int unsigned get(random_delay_type_e kind = REGULAR);
    set_delay(kind);
    return(delay);
  endfunction: get

// --------------------------------------------------------------------
endclass: random_delay