Bitwise rotation???

[FreewareFire]

Please have a look here,

http://www.computerhelp.forum/t74824/s.html


- Sorry, dont know where to post this thread!?

 

[reanjr]

Try something along the lines of

i = (i << 1) | (i >> 31);

 

[reanjr]

/* This should work. I tried it in VB real quick, but not C#
Should be a lot quicker than the other version as well
Warning: may have problem with signed integers
I dont know how .NET treats them on bit shifts */

val = (val << 1) | (val >> 31);

 

[FreewareFire]

Thx - will try!

 

[FreewareFire]

Ive found this...


#define ROTR(x,y,b) (((x)>>(y&((b)-1))) | ((x)<<((b)-(y&((b)-1)))))

its for C++

could someone translate it to C# ?

x is value, y how many rotates and b how many bits the value has... Thx

isnt there a simplier way? Im really confused!

 

[OnErr0r]

Im very new to C#, but what if you created a generic function like this:

    uint RolRight(uint x, byte y, byte b) // number, shift, bits
    {
      //#define ROTR(x,y,b) (((x)>>(y&((b)-1))) | ((x)<<((b)-(y&((b)-1)))))
      return (x >> (y & (b - 1))) | (x << (b - (y & (b - 1))));
    }

And called it like one of these:

byte Ret = (byte)RolRight(0x81, 1, 8);
ushort Ret = (ushort)RolRight(0x8001, 1, 16);
uint Ret = RolRight(0x80000001, 1, 32);

 

[FreewareFire]

This one looks very good! I will try it! Thank you!!!

 

[FreewareFire]

I forget to tell anyone: It works great!!!!