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Re: ProDOS and the random seed RNDL

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From	D Finnigan <dog_cow@macgui.com>
Newsgroups	comp.sys.apple2.programmer
Subject	Re: ProDOS and the random seed RNDL
Date	Wed, 23 Dec 2015 19:39:44 -0000 (UTC)
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awanderin wrote:
> D Finnigan <dog_cow@macgui.com> writes:
> 
>> Since converting the Marina IP source from DOS 3.3 to ProDOS, I've
>> noticed
>> that link-local addresses, which were previously randomly generated, were
>> no
>> longer random. I took the time to track down this issue yesterday.
>>
>> I'm using ProDOS 8 v1.9 on an enhanced (platinum) Apple IIe but I believe
>> all versions of ProDOS have this problem.
>>
>> I had been using RNDL and RNDH ($4E and $4F) as my random seed. I put
>> together this program to test what was happening:
>>
>> A5 4E
>> 20 DA FD
>> A5 4F
>> 20 DA FD
>> 4C D0 03
>>
>> ]BRUN RND
>> 0D80
>>
>> *8000G
>> 958E
>
> 
> I don't know the internals of Marina, but if you have control of when
> ProDOS is called, perhaps Get_Prefix in particular, you could just save
> RNDL/H on the stack before issuing the MLI call.  Having to call an
> interactive routine seems an ugly workaround unless you actually want
> some user input.

The little test program I made shows that ProDOS sets RNDL and RNDH before
control passes to my program.

I agree, I don't like the work-around. But many applications that use Marina
will probably involve keyboard input at some point.

-- 
]DF$
The Marina IP stack for Apple II--
http://marina.a2hq.com/

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Thread

ProDOS and the random seed RNDL D Finnigan <dog_cow@macgui.com> - 2015-12-21 19:45 +0000
  Re: ProDOS and the random seed RNDL awanderin <awanderin@gmail.com> - 2015-12-22 23:38 -0700
    Re: ProDOS and the random seed RNDL D Finnigan <dog_cow@macgui.com> - 2015-12-23 19:39 +0000
  Re: ProDOS and the random seed RNDL gids.rs@sasktel.net - 2015-12-23 09:23 -0800
    Re: ProDOS and the random seed RNDL D Finnigan <dog_cow@macgui.com> - 2015-12-23 19:51 +0000
      Re: ProDOS and the random seed RNDL gids.rs@sasktel.net - 2015-12-23 17:25 -0800
        Re: ProDOS and the random seed RNDL D Finnigan <dog_cow@macgui.com> - 2016-01-04 19:02 +0000

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