RANDOM() a litle bit more random please...

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 3:51 pm

Restored from previous forum. Originally posted by FAKEFACTORY.

Hi,

i there any way to make more random random-numbers out of the RANDOM() function? I.e. RANDOM(7)+1 for random numbers between 1 and 8 gives me
mainly:

1,1,1,1,5,5,5,1,5,5,5,1,....

This is a little bit to static for a random generator. Can we "load" the function with a randomizer-seed, like CurrentTicks? Or is there another Random-generator sourcecode avaiable?

Registered PureBasic Coder

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 5:09 pm

Restored from previous forum. Originally posted by El_Choni.

Hi, try this code:

Code: Select all

    Global result.l

    max.l
    seed.l

!Extern _GetTickCount@0
!call _GetTickCount@0
!mov [v_seed], eax

Procedure.l MyRandom(max.l) ; don't use 0 as max, or fires a division by 0 error (avoidable, but would make it slower)
    !mov [v_max], eax
    !mov eax, [v_seed] 
    !mov dword ecx, $41c64e6d 
    !mul ecx 
    !add dword eax, $3039 
    !And dword eax, $7ffffff 
    !mov [v_seed], eax 
    !mov ecx, [v_max]
    !sub edx, edx 
    !div ecx 
    !mov [v_result], edx
    ProcedureReturn result
EndProcedure

result = MyRandom(7)
MessageRequester("Random result:", Str(result), 0)

Bye,

El_Choni

Edited by - El_Choni on 03 February 2002 17:23:47

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 5:24 pm

Restored from previous forum. Originally posted by Paul.

Excellent procedure El_Choni !!

Just a note, make sure you reseed off the system clock or something... else you will receive the same set of random numbers every time you restart your program.

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 5:43 pm

Restored from previous forum. Originally posted by El_Choni.

"reseed off"? I don't understand. the GetTickCount call is used to get a different seed each time, precisely to avoid what you say.

I got this code from the Win32asm message board. There are several other pseudorandom number generators there, check it if you wish.

Bye,

El_Choni

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 5:51 pm

Restored from previous forum. Originally posted by MrVainSCL.

Hi El_Choni
Many many thanks for your suppport to optimize the Random() and Str() commands... The new Random() works very fine... I must test the Str() replace... Anyway many thanks for the friendly and fast support - now my program is a bit smaller

) Would be nice to see the feature in next PB where danilo told about... Link only needed stuff to a file (obj) ...

) This would be very welcome Fred!

PIII450, 256MB Ram, 6GB HD, RivaTNT, DirectX8.1, SB AWE64, Win98SE + Updates...

greetz
MrVainSCL! aka Thorsten

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 6:06 pm

Restored from previous forum. Originally posted by Paul.

You have since edited the version posted.
The version I copy and pasted had a set seed (seed.l=5555), it did not have the GetTickCount.

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 6:16 pm

Restored from previous forum. Originally posted by DarkUni.

We should probably get Fred to add a RANDOMIZE command native.

Then we could the system timer to randomize easier.

This is definitely vital to video game coding.

Shane R. Monroe
Dark Unicorn Productions

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 7:01 pm

Restored from previous forum. Originally posted by El_Choni.

You have since edited the version posted.
The version I copy and pasted had a set seed (seed.l=5555), it did not have the GetTickCount.

He, he, I saw my error and corrected it, but thought that your post was made after the correction.

Bye,

El_Choni

BackupUser · Post by **BackupUser** » Sun Feb 03, 2002 7:46 pm

Restored from previous forum. Originally posted by FAKEFACTORY.

@El_Choni
Great code! Many thanks

Registered PureBasic Coder

BackupUser · Post by **BackupUser** » Mon Feb 04, 2002 5:57 pm

Restored from previous forum. Originally posted by MrVainSCL.

is this for any OS? -jb

sorry... the lib will be coded in pure x86 code... also it dont want run on 680x0 amiga os for example...

PIII450, 256MB Ram, 6GB HD, RivaTNT, DirectX8.1, SB AWE64, Win98SE + Updates...

greetz
MrVainSCL! aka Thorsten

BackupUser · Post by **BackupUser** » Mon Feb 04, 2002 6:18 pm

Restored from previous forum. Originally posted by El_Choni.

Tron, if you talk about the randomizing procedure, it must be easy to translate (anyway, PB Amiga will be updated soon and will likely include the Random() function, I guess).

Here's a rough translation using 86TO68:

Code: Select all

Data:

seed: dc.l 0

Code:

PB_InitRandom:
 jsr  _GetTickCount@0 ; this should be changed to some Amiga API function which puts the result in d0
 move.l d0,seed
 rts

PB_Randomize:
 move.l d0,-(a7)
 move.l seed(pc),d0
 move.l #1103515245,d2
 add.l  #12345,d0
 and.l  #134217727,d0
 move.l d0,seed
 move.l (a7)+,d2
 sub.l  d3,d3
 move.l d0,d5
 move.l d3,d0
 move.l d5,d3
 rts

See you,

Edited by - El_Choni on 04 February 2002 18:44:46

BackupUser · Post by **BackupUser** » Tue Feb 05, 2002 1:12 am

Restored from previous forum. Originally posted by El_Choni.

I'm quite sure it won't work without testing and correcting, which I can't do because I lost my WinUAE instalation and my A4000/40 is 600 Km. away.

But it's a start

Bye,

El_Choni

BackupUser · Post by **BackupUser** » Tue Feb 05, 2002 10:30 am

Restored from previous forum. Originally posted by PB.

> I lost my WinUAE instalation

I just installed the latest WinUAE and wow: it's so FAST now! I can
actually play Alien Breed 3D at a respectable speed! Very good work
by whoever added the JIT code to it.

PB - Registered PureBasic Coder

BackupUser · Post by **BackupUser** » Tue Feb 05, 2002 11:29 am

Restored from previous forum. Originally posted by El_Choni.

I think that what is so fast now is your computer

. I'm going to install it again, but don't know where to find a good assembler to test things, and CygnusEd, (oh, well, and so much other things that don't come with UAE, of course).

Have a nice day,

El_Choni

BackupUser · Post by **BackupUser** » Tue Feb 05, 2002 11:37 am

Restored from previous forum. Originally posted by fred.

search for PhxAss.. and GoldED.

Fred - AlphaSND