Random Float Generator

[Adamanteus]

Some assembler alternative to very much scientific algos to get float random number in given range 

[Vortex]

Hi Adamanteus,

Try to combine your random number generator with Windows' system timer. On every execution of your application, you will get a different list of numbers.

[jj2007]

Here is a version that is compatible with a standard Masm32 installation, i.e. no environment variables required. I haven't changed anything substantial.

As to the quality of the generated numbers: you are using nrandom, which afaik has been tested a lot in the old forum, e.g. here.

[Adamanteus]

Try to combine your random number generator with Windows' system timer. On every execution of your application, you will get a different list of numbers.

Algorithm done for built-in whole numbers random generator, it could be crt_rand, nrandom and all others, and random seed for it is need to add by hand – crt_srnad or unknown eax value and all others   ::)

[Vortex]

Here is a quick crt_rand example :

Code Select Expand


include     \masm32\include\masm32rt.inc

.data

    f1      db 'Number %d = %d',13,10,0

.code

start:

    call    main
    invoke  ExitProcess,0

main PROC uses esi ebx

LOCAL _st:SYSTEMTIME

    invoke  GetSystemTime,ADDR _st
    movzx   ebx,SYSTEMTIME.wMilliseconds[_st]
@@:
    invoke  crt_rand
    dec     ebx
    jnz     @b

    mov     esi,100
    mov     ebx,10
@@:
    invoke  crt_rand
    xor     edx,edx
    div     esi
    invoke  crt_printf,ADDR f1,ebx,edx
    dec     ebx
    jnz     @b
    ret
   
main ENDP

END start


[MichaelW]

One potential problem with the CRT rand function is the 15-bit range.

As a test I decided to do a scatter plot of the randf_size return values. The plot showed no problems, but to make it work I had to modify randf_size.asm.

[Vortex]

Hi MichaelW,

Nice example. You should modify the batch file makeit.bat to build the application as GUI.

[MichaelW]

Hi Vortex,

I left it as a console app so that by uncommenting the printf, Sleep, and FLD ST statements it would be easy to see what is wrong.

[bluedevil]

Hi all,
After reading this topic, i have prepared my own random real number generator. Not perfect but gives an idea.

Also i edited your sample codes as a radasm project, i attached them

Finally, i wanna share your randf.asm and sample codes on my website, if it is not problem for you, @MichaelW, @Adamanteus ??

[Adamanteus]

From me it's absolute  freeware - do anything you want, except patent as invention of you own.

[bluedevil]

Aha thanks a lot i have been waiting for this comment :t i will publish these on my blog