[vcf-midatlantic] Random numbers
bob at corshamtech.com
Sat Apr 8 13:16:14 EDT 2017
> On Apr 8, 2017, at 1:06 PM, Dave McGuire via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> On 04/08/2017 12:10 PM, Dan Roganti via vcf-midatlantic wrote:
>>> that step to seed the rnd generator is not perfect either
>>> , eg. RND(-32768) or whichever value
>>> if you use the same seed, guess what,
>>> you get the same random numbers :)
>> This is why you like to use something "random" to seed the rnd generator
>> Usually every computer has a free running counter,
>> meaning it's constantly being updated in the background
> If some of my dustiest neurons are working, in the Atari at least there's a scan line counter from the video subsystem available for reading. At least I think it was something like that. That was great for seeding random number generators. The Apple ][ must have something like that.
Or just use a software “timer”, like the delay until the user does something, like move the joystick, press a key, etc. Ie, sit in a loop waiting for something to happen, incrementing a counter each time through. When the user finally does something, use the counter as a seed.
Another option is to just sum up all of RAM memory since it’s unlikely exactly the same thing will be in every memory location each run.
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