[*
 * (seed) lsx --
 * Seeds the subtractive generator.
 * Uses register R to hold the state.
 *]sz
[
 [* Fill ring buffer R[0] to R[54]. *]sz
 d 54:R SA              [A = R[54] = seed]sz
 1 d 33:R SB            [B = R[33] = 1]sz
 12 SC                  [C = index 12, into array R.]sz
 [55 -]SI
 [                      [Loop until C is 54:]sz
  lA lB - d lC:R         [R[C] = A - B]sz
  lB sA sB               [Parallel let A = B and B = A - B]sz
  lC 34 + d 55 !>I d sC  [C += 34 (mod 55)]sz
  54 !=L
 ]d SL x
 [* Point R[55] and R[56] into ring buffer. *]sz
 0 55:R                 [R[55] = index 0, of 55th last number.]sz
 31 56:R                [R[56] = index 31, of 24th last number.]sz
 [* Stir ring buffer. *]sz
 165 [                  [Loop 165 times:]sz
  55;R;R 56;R;R - 55;R:R [Discard a random number.]sz
  55;R 1 + d 55 !>I 55:R [R[55] += 1 (mod 55)]sz
  56;R 1 + d 55 !>I 56:R [R[56] += 1 (mod 55)]sz
  1 - d 0 <L
 ]d sL x
 LAsz LBsz LCsz LIsz LLsz
]ss

[*
 * lrx -- (random number from 0 to 10^9 - 1)
 * Returns the next number from the subtractive generator.
 * Uses register R, seeded by lsx.
 *]sz
[
 55;R;R 56;R;R -        [R[R[55]] - R[R[56]] is next random number.]sz
 d 55;R:R               [Put it in R[R[55]]. Also leave it on stack.]sz
 [55 -]SI
 55;R 1 + d 55 !>I 55:R [R[55] += 1 (mod 55)]sz
 56;R 1 + d 55 !>I 56:R [R[56] += 1 (mod 55)]sz
 [1000000000 +]sI
 1000000000 % d 0 >I    [Random number = it (mod 10^9)]sz
 LIsz
]sr


[* Seed with 292929 and print first three random numbers. *]sz
292929 lsx
lrx psz
lrx psz
lrx psz