[src/trunk]: src/lib/libc/gen correct setup of ru_b/a for 16/20 bit case

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8572191871c1
branches:  trunk
changeset: 551901:8572191871c1
user:      itojun <itojun%NetBSD.org@localhost>
date:      Sat Sep 13 21:29:57 2003 +0000

description:
correct setup of ru_b/a for 16/20 bit case

diffstat:

 lib/libc/gen/randomid.c |  9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diffs (30 lines):

diff -r 7af2a10de577 -r 8572191871c1 lib/libc/gen/randomid.c
--- a/lib/libc/gen/randomid.c   Sat Sep 13 21:27:43 2003 +0000
+++ b/lib/libc/gen/randomid.c   Sat Sep 13 21:29:57 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: randomid.c,v 1.5 2003/09/13 21:27:43 itojun Exp $      */
+/*     $NetBSD: randomid.c,v 1.6 2003/09/13 21:29:57 itojun Exp $      */
 /*     $KAME: ip6_id.c,v 1.8 2003/09/06 13:41:06 itojun Exp $  */
 /*     $OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $       */
 
@@ -88,7 +88,7 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: randomid.c,v 1.5 2003/09/13 21:27:43 itojun Exp $");
+__RCSID("$NetBSD: randomid.c,v 1.6 2003/09/13 21:29:57 itojun Exp $");
 #endif
 
 #include "namespace.h"
@@ -221,8 +221,9 @@
        p->ru_seed2 = arc4random() & (~0U >> (32 - p->ru_bits + 1));
 
        /* Determine the LCG we use */
-       p->ru_b = arc4random() | 1;
-       p->ru_a = pmod(p->ru_agen, arc4random() & (~1U), p->ru_m);
+       p->ru_b = (arc4random() & (~0U >> (32 - p->ru_bits))) | 1;
+       p->ru_a = pmod(p->ru_agen,
+           (arc4random() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
        while (p->ru_b % 3 == 0)
                p->ru_b += 2;