Cshift function in C?

[fabien]

Hi!

I am trying to find an equivalent to Fortran Cshift function in C/C++ can someone please help?

Thanks!

 

[Zyrenthian]

I am not sure if the shift direction is correct but this is the basic idea to do a circular shift. Please keep in mind that the function assumes that the number of bits to shift will be in the range 0-31. You can allow any value but implimenting the % operator on shift and mod by 31 (i think).

Matt

int CShift(int value, int shift)
{
	int high = 0;
	int low = 0;
	if(shift<0)
	{
		 // left shift
		int sh = shift*-1;
		high = value<<sh;
		low = value>>(32-sh);
	}
	else
	{
		// right shift
		low = value>>shift;
		high =  value<<(32-shift);
	}
	return high | low;
}

Matt

 

[Zyrenthian]

Actually, looking at that, i dont think it works 100%. Please test the code.

Matt

 

[fabien]

Thanks I'll try this..