The logic for additional randomisation for 64-bit UV

cases was wrong.

p4raw-id: //depot/perl@20009

diff --git a/perl.c b/perl.c
index c7a8282..bf707c0 100644 (file)
--- a/perl.c
+++ b/perl.c
@@ -917,12 +917,12 @@ setuid perl scripts securely.\n");
            PL_srand_called = TRUE;
            PL_hash_seed = (UV)(Drand01() * (NV)UV_MAX);
 #if RANDBITS < (UVSIZE * 8)
-           {
-               int skip = (UVSIZE * 8) - RANDBITS;
-               PL_hash_seed >>= skip;
-               /* The low bits might need extra help. */
-               PL_hash_seed += (UV)(Drand01() * ((1 << skip) - 1));
-           }
+          /* Since there are not enough randbits to to reach all
+           * the bits of a UV, the low bits might need extra
+           * help.  Sum in another random number that will
+           * fill in the low bits. */
+          PL_hash_seed +=
+            (UV)(Drand01() * (NV)((1 << ((UVSIZE * 8 - RANDBITS))) - 1));
 #endif /* RANDBITS < (UVSIZE * 8) */
        }
 #endif /* USE_HASH_SEED_EXPLICIT */