Error using shift and power operator

[Altera_Forum]

Hi; 

I am getting error using sla and ** operators. My code is as under : Rx_Buff_i : in STD_LOGIC_VECTOR (7 downto 0); . . . signal Chksum : std_logic_vector(7 downto 0) := (others => '0'); signal Shft_buff : std_logic_vector(1607 downto 0) :=(others => '0'); . . . . Shft_buff<= Shft_buff sla 8; Chksum <= Chksum ** Rx_Buff_i; I am including the following libraries: use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_unsigned.ALL; use IEEE.std_logic_arith.all; use IEEE.numeric_std.ALL; The following errors I am getting 1)found '0' definitions of operator "sla", cannot determine exact overloaded matching definition for "sla" 2) found '0' definitions of operator "**", cannot determine exact overloaded matching definition for "**" plz help

[Altera_Forum]

--- Quote Start ---  Hi; I am getting error using sla and ** operators.  I am including the following libraries: use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_unsigned.ALL; use IEEE.std_logic_arith.all; use IEEE.numeric_std.ALL;  --- Quote End ---    Please, don't use numeric_std and std_logic_arith/unsigned at the same time! That makes for a lot of type confusion. Use numeric_std only.    --- Quote Start ---  Shft_buff<= Shft_buff sla 8; Chksum <= Chksum ** Rx_Buff_i;  The following errors I am getting 1)found '0' definitions of operator "sla", cannot determine exact overloaded matching definition for "sla"   --- Quote End ---    Regarding the sla operator, it is not defined for std_logic_vector. It is defined (in numeric_std) for unsigned and signed, but they're problematic and nobody uses them (and they may not synthesize). Instead, just use the usual shift left:  ShiftLeft : process (clk) is begin if rising_edge(clk) then foo <= foo(foo'left - 1 downto 0) & '0'; end if; end process ShiftLeft;    --- Quote Start ---   2) found '0' definitions of operator "**", cannot determine exact overloaded matching definition for "**" plz help  --- Quote End ---    The exponent has to be:  a) a constant (compile-time) integer. It cannot be a variable and it certainly cannot be a std_logic_vector. b) a power-of-two, which means it is implemented as a shift left.  So just use the shift left.