Sv: Sv: Sv: Sv: A83: Random values


Sv: Sv: Sv: Sv: A83: Random values

Oh _thats_ what you mean by writeback. I thought you meant writeback as in storing the value for next time the program is run...

-----Oprindelig meddelelse-----
Fra: Phelan Wolf <>
Til: <>
Dato: 12. september 1998 00:43
Emne: Re: Sv: Sv: Sv: A83: Random values

>ok, writeback isn't hard.
>make a label at the end of your program, like this:
>and allocate it 1 byte like this:
>lastRandom: .db $00
>now we have where we place the random number.  We do it like so...
>;code getting random number into 'e'
>ld hl,lastRandom     ;get ready to copy the random number
>ex a,e               ;exchange 'a' and 'e', putting the random number                      
>;from 'e' into 'a', while not destroying 'a'
>ld (hl),a            ;(hl) is the memory location, lastRandom, and we
>                     ;just put the random number into there
>ex a,e               ;restore the registors 'a' and 'e' by putting                      
>;back the origional values
>hope this helps, any questions just ask.
>-Phelan 'Amen' Wolf
>>From Fri 
>Sep 11 11:48:46 1998
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>>From: "Thomas Turn Jensen" <>
>>To: <>
>>Subject: Sv: Sv: Sv: A83: Random values
>>Date: Fri, 11 Sep 1998 20:49:55 +0200
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>>Ah.... That last thing sounds interesting...
>>the writing back thing is kinda tricky.. Wouldn't know how to do that 
>yet - and any explanation ppl could get me would still be too technical 
>I'm afraid... but just wait.. maybe next week I'll ask....
>>Thanks again for the great delay measuring trick.
>>-----Oprindelig meddelelse-----
>>Fra: Linus Akesson <>
>>Til: Thomas Turn Jensen <>
>>Dato: 11. september 1998 20:45
>>Emne: Re: Sv: Sv: A83: Random values
>>>Yupp. So you can do a writeback to the program, saving the last random 
>>>and reading it back as the first random number when the program is run 
>>>Another widely used method is to check how long time the user waits 
>>>pressing a key. This would involve using your own key loop, instead of
>>>On 11-Sep-98, Thomas Turn Jensen wrote:
>>>>But if I start with a constant - wouldn't my program just come up 
>with the
>>>>same random numbers everytime it is run?
>>>>This may be a stupid question, but I simply doesn't follow you.. Care 
>>>>explain more (plz :-)?
>>>>-----Oprindelig meddelelse-----
>>>>Fra: Linus Akesson <>
>>>>Til: Thomas Turn Jensen <>
>>>>Dato: 11. september 1998 18:30
>>>>Emne: Re: Sv: A83: Random values
>>>>>You don't. Use a constant, or the contents of some register at 
>program start
>>>>>or whatever. The random routines in the os always start with the 
>>>>>I think it is 0.94 or something the first time you use math->rand 
>with new
>>>>>On 10-Sep-98, Thomas Turn Jensen wrote:
>>>>>>..ehm.. How do I get that Starting random # ?
>>>>>>-----Oprindelig meddelelse-----
>>>>>>Fra: Linus Akesson <>
>>>>>>Til: Thomas Turn Jensen <>
>>>>>>Dato: 10. september 1998 21:02
>>>>>>Emne: Re: A83: Random values
>>>>>>>Random algorithms are quite numerous out there... one idea is to 
>take the
>>>>>>>previous random number you got, rotate it some, add some, eor 
>some, then
>>>>>>>the program and see if there's a visible pattern. If there is, 
>change some
>>>>>>>the constants and try again...
>>>>>>>On 10-Sep-98, Thomas Turn Jensen wrote:
>>>>>>>>I need to get two random values...
>>>>>>>>one in the range [0..94] and the other in [1..64] (yes you guesed 
>it -
>>>>>>>>for the graph-screen)
>>>>>>>>I've found a function called "_Random" but have no idea what 
>>>>>>>>takes where - nor what/where the output is...
>>>>>>>>Could someone either explain to me how it works or tell me how to 
>>>>>>>>something which results in the above mentined numbers. (If i get 
>>>>>>>>that results in a random byte thats ok - where I need it, speed 
>>>>>>>>essential so I can just check it and if not good generate another 
>>>>>>>>In case someone gives me some code, _plz_ explain what it does as 
>>>>>>>>interesting in learning how to make it rather than always use 
>>>>>>>>Thank you.
>>>>>>>>Thomas Turn Jensen
>>>>>>>>Icq uin => 8128636
>>>>>>>>IRC, Undernet => Mukke
>>>>>>>>If your computer gives you trouble
>>>>>>>>Call for Mukke on the double
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