[PATCH] rand.c updates from FreeBSD RELENG_5

Joerg Sonnenberger joerg at britannica.bec.de
Wed May 12 05:20:16 PDT 2004


On Wed, May 12, 2004 at 06:11:21AM -0500, William M. Grim wrote:
> I have included the patch, but to see what I mean about the current 
> rand(3) not being great, try this code (yes, I know, the seeding could 
> have been done better):
> 
[snip]
>                 cs = rand() % 2;
[snip]

In any good book about the rand() PRNG and in random(3) is a note that the
lower bits have a very low entropy. E.g. chance the code to
	cs = (rand() >> 8) % 2;
provides much better results.

Joerg





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