1. BARREL SHIFTER

2. A barrel shifter is a digital circuit that can shift a data word by a specified number of bits in one clock cycle.
Shifts the input data in combinational manner
It can be implemented as a sequence of multiplexers (mux.) or FET
A common usage of a barrel shifter is in the hardware implementation of floating-point arithmetic.

4. PROGRAM library IEEE; use IEEE.STD_1164.all entity BARREL_SHIFTER is
Generic (N: POSITIVE:= 4);
Port( DATA:in STD_LOGIC_VECTOR(N-1 down to 0));
SELEKT : in INTEGER range 0 to N-1;
BARR_OUT : out STD_LOGIC_VECTOR ( N-1 down to 0));
end BARREL_SHIFTER;
architechture FOR_LOOP_STYLE of BARREL_SHIFTER is
begin
process(SELEKT,DATA)
variable VAR_BUF: STD_LOGIC_VECTOR( N-1 down to 0));
VAR_BUF:=DATA;

5. for K in 1 to SELEKT LOOP
VAR_BUF := VAR_BUF(N-2 down to 0)& VAR_BUF(N-1);
end loop;
BARR_OUT<= VAR_BUF;
end process;
end FOR_LOOP_STYLE;
architecture CONCURRENT_STYLE of BARREL_SHIFTER is
begin
BARRE_OUT<= DATA(N-1- SELEKT down to 0)&
DATA(N-1 down to N- SELEKT)
When SELEKT> 0;
else DATA;
end CONCURRENT _STYLE;