Rotate_operator in VHDL

rol can not have such operands in this context

in my code i have to rotates the data left/right by a variable amount k.
but it shows me Error ...The error is ror and rol can not have such operands in this context............

Can any one do tell me how can i remove this error........

my code is..........


library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.NUMERIC_BIT.ALL;


entity rotate_operator is
generic(w: integer :=8; size: integer :=3);
port(A : in std_logic_vecor(w-1 downto 0);
k : in std_logic_vecor(size-1 downto 0);
o : out std_logic_vecor(w-1 downto 0));
end rotate_operator;






architecture arch_rotate_operator of rotate_operator is
begin
process(A , k)
begin
o <= ((A ror k) or (A rol k));


end arch_rotate_operator

rol can not have such operands in this context.

How did you define the ror & rol functions ?

ror can not have such operands in this context

Mate, I cannot help you with your code, nevertheless, I have written two functions i.e 'crr' and 'crl' which will do what you want. If you like, feel free to use them
And here they are:
http://www.vlsiip.com/vhdlf.html
Kr,
Avi
http://www.vlsiip.com

ror en vhdl

Hi,
- Check if you included the library wich contain the function rors and rols.
- How did you the rotating fucntions. Perhaps errors are there

ROtate separately ,assign to signal temp and then perform oring not simulatnously. plz try this.