(* This is a port of the System3 or V4 RNG.
You should use Random.Mod instead. *)
MODULE RandomNumbers;
  IMPORT Texts, Oberon, SYSTEM;

  VAR z, td: INTEGER;
    W: Texts.Writer;

  PROCEDURE Uniform*(): REAL;
    CONST a = 16807; m = 2147483647;
      q = m DIV a; r = m MOD a;
    VAR g: INTEGER;
  BEGIN
    g := a * (z MOD q) - r * (z DIV q);
    Texts.WriteInt(W, g, 12); Texts.WriteLn(W);
    IF g > 0 THEN z := g ELSE z := g + m END;
    Texts.WriteInt(W, z, 12); Texts.WriteLn(W);
    RETURN FLT(z) * 1.0 / FLT(m)
  END Uniform;

  PROCEDURE InitSeed*(seed: INTEGER);
  BEGIN z := seed
  END InitSeed;

  PROCEDURE Test*;
  BEGIN Texts.WriteReal(W, Uniform(), 12); Texts.WriteLn(W);
    Texts.Append(Oberon.Log, W.buf)
  END Test;

(* The Pepino RTC never ticks.
And a time of 0 is an edge case that always gives the same "random" number.
Everything works fine if you manually set the time with System.Date first.
TODO: is there any other entropy hardware?
A: doesn't look like it from the schematics *)
BEGIN Texts.OpenWriter(W);
  td := Oberon.Clock();
  Texts.WriteInt(W, td, 12); Texts.WriteLn(W);
  z := SYSTEM.VAL(INTEGER, td);
  Texts.WriteInt(W, z, 12); Texts.WriteLn(W);
END RandomNumbers.