VHDL code PROBLEM ,how to create shift left operation without register in vhdl

[shifter2013]

Hi!
I have problem to create shift left operation with 4 bit input to 4bitni output?
So, I have to create shiftleft component for my ALU but that shifter must have 4bitni input and 4 bit output.
Does vhdl have some operation for shift ? I try to put sll operation but does not work.
I also try 4bit input to multiply with 2 but does not work correctly for all combinations.
I know that component can create with register but that does not work because i have to have 4 bit input and 4 output.

 

[yamine]

try this:
if A is your input and B your output:
B<='0' & A(3 downto 1) ;

 

[moottii]

Use SLL
I think your operands are "std_logic_vector"
SLL is defined for "bit" type
first convert your input to "bit" type and then use SLL