* rand.c (rand32): Moved.

(make_random_state): After initializing, retrieve eight
random numbers to clear pathological initial behavior
leading to duplicate values.

1 files changed, 25 insertions, 21 deletions

diff --git a/rand.c b/rand.c
index 073aa62e..9a48e7e1 100644
--- a/rand.c
+++ b/rand.c
@@ -80,9 +80,31 @@ val random_state_p(val obj)
   return typeof(obj) == random_state_s ? t : nil;
 }
 
+static rand32_t rand32(struct random_state *r)
+{
+  #define RSTATE(r,i) ((r)->state[((r)->cur + i) % 16])
+  rand32_t s0 = RSTATE(r, 0);
+  rand32_t s9 = RSTATE(r, 9);
+  rand32_t s13 = RSTATE(r, 13);
+  rand32_t s15 = RSTATE(r, 15);
+
+  rand32_t r1 = s0 ^ (s0 << 16) ^ s13 ^ (s13 << 15);
+  rand32_t r2 = s9 ^ (s9 >> 11);
+
+  rand32_t ns0 = RSTATE(r, 0) = r1 ^ r2;
+  rand32_t ns15 = s15 ^ (s15 << 2) ^ r1 ^ (r1 << 18) ^ r2 ^ (r2 << 28) ^ 
+                  ((ns0 ^ (ns0 << 5)) & 0xda442d24ul);
+
+  RSTATE(r, 15) = ns15;
+  r->cur = (r->cur + 15) % 16;
+  return ns15;
+  #undef RSTATE
+}
+
 val make_random_state(val seed)
 {
   val rs = make_state();
+  int i;
   struct random_state *r = (struct random_state *) 
                              cobj_handle(rs, random_state_s);
 
@@ -126,28 +148,10 @@ val make_random_state(val seed)
               seed, nao);
   }
 
-  return rs;
-}
+  for (i = 0; i < 8; i++)
+    (void) rand32(r);
 
-static rand32_t rand32(struct random_state *r)
-{
-  #define RSTATE(r,i) ((r)->state[((r)->cur + i) % 16])
-  rand32_t s0 = RSTATE(r, 0);
-  rand32_t s9 = RSTATE(r, 9);
-  rand32_t s13 = RSTATE(r, 13);
-  rand32_t s15 = RSTATE(r, 15);
-
-  rand32_t r1 = s0 ^ (s0 << 16) ^ s13 ^ (s13 << 15);
-  rand32_t r2 = s9 ^ (s9 >> 11);
-
-  rand32_t ns0 = RSTATE(r, 0) = r1 ^ r2;
-  rand32_t ns15 = s15 ^ (s15 << 2) ^ r1 ^ (r1 << 18) ^ r2 ^ (r2 << 28) ^ 
-                  ((ns0 ^ (ns0 << 5)) & 0xda442d24ul);
-
-  RSTATE(r, 15) = ns15;
-  r->cur = (r->cur + 15) % 16;
-  return ns15;
-  #undef RSTATE
+  return rs;
 }
 
 val random_fixnum(val state)