end;


    function "/="(L: SIGNED; R: UNSIGNED) return BOOLEAN is
	constant length: INTEGER := max(L'length, R'length + 1);
    begin
	return bitwise_neq( STD_ULOGIC_VECTOR( CONV_SIGNED(L, length) ),
		STD_ULOGIC_VECTOR( CONV_SIGNED(R, length) ) );
    end;


    function "/="(L: UNSIGNED; R: INTEGER) return BOOLEAN is
	constant length: INTEGER := L'length + 1;
    begin
	return bitwise_neq( STD_ULOGIC_VECTOR( CONV_SIGNED(L, length) ),
		STD_ULOGIC_VECTOR( CONV_SIGNED(R, length) ) );
    end;


    function "/="(L: INTEGER; R: UNSIGNED) return BOOLEAN is
	constant length: INTEGER := R'length + 1;
    begin
	return bitwise_neq( STD_ULOGIC_VECTOR( CONV_SIGNED(L, length) ),
		STD_ULOGIC_VECTOR( CONV_SIGNED(R, length) ) );
    end;


    function "/="(L: SIGNED; R: INTEGER) return BOOLEAN is
	constant length: INTEGER := L'length;
    begin
	return bitwise_neq( STD_ULOGIC_VECTOR( CONV_SIGNED(L, length) ),
		STD_ULOGIC_VECTOR( CONV_SIGNED(R, length) ) );
    end;


    function "/="(L: INTEGER; R: SIGNED) return BOOLEAN is
	constant length: INTEGER := R'length;
    begin
	return bitwise_neq( STD_ULOGIC_VECTOR( CONV_SIGNED(L, length) ),
		STD_ULOGIC_VECTOR( CONV_SIGNED(R, length) ) );
    end;



    function SHL(ARG: UNSIGNED; COUNT: UNSIGNED) return UNSIGNED is
	constant control_msb: INTEGER := COUNT'length - 1;
	variable control: UNSIGNED (control_msb downto 0);
	constant result_msb: INTEGER := ARG'length-1;
	subtype rtype is UNSIGNED (result_msb downto 0);
	variable result, temp: rtype;
    begin
	control := MAKE_BINARY(COUNT);
	if (control(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := ARG;
	for i in 0 to control_msb loop
	    if control(i) = '1' then
		temp := rtype'(others => '0');
		if 2**i <= result_msb then
		    temp(result_msb downto 2**i) := 
				    result(result_msb - 2**i downto 0);
		end if;
		result := temp;
	    end if;
	end loop;
	return result;
    end;

    function SHL(ARG: SIGNED; COUNT: UNSIGNED) return SIGNED is
	constant control_msb: INTEGER := COUNT'length - 1;
	variable control: UNSIGNED (control_msb downto 0);
	constant result_msb: INTEGER := ARG'length-1;
	subtype rtype is SIGNED (result_msb downto 0);
	variable result, temp: rtype;
    begin
	control := MAKE_BINARY(COUNT);
	if (control(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := ARG;
	for i in 0 to control_msb loop
	    if control(i) = '1' then
		temp := rtype'(others => '0');
		if 2**i <= result_msb then
		    temp(result_msb downto 2**i) := 
				    result(result_msb - 2**i downto 0);
		end if;
		result := temp;
	    end if;
	end loop;
	return result;
    end;


    function SHR(ARG: UNSIGNED; COUNT: UNSIGNED) return UNSIGNED is
	constant control_msb: INTEGER := COUNT'length - 1;
	variable control: UNSIGNED (control_msb downto 0);
	constant result_msb: INTEGER := ARG'length-1;
	subtype rtype is UNSIGNED (result_msb downto 0);
	variable result, temp: rtype;
    begin
	control := MAKE_BINARY(COUNT);
	if (control(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := ARG;
	for i in 0 to control_msb loop
	    if control(i) = '1' then
		temp := rtype'(others => '0');
		if 2**i <= result_msb then
		    temp(result_msb - 2**i downto 0) := 
					result(result_msb downto 2**i);
		end if;
		result := temp;
	    end if;
	end loop;
	return result;
    end;

    function SHR(ARG: SIGNED; COUNT: UNSIGNED) return SIGNED is
	constant control_msb: INTEGER := COUNT'length - 1;
	variable control: UNSIGNED (control_msb downto 0);
	constant result_msb: INTEGER := ARG'length-1;
	subtype rtype is SIGNED (result_msb downto 0);
	variable result, temp: rtype;
	variable sign_bit: STD_ULOGIC;
    begin
	control := MAKE_BINARY(COUNT);
	if (control(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := ARG;
	sign_bit := ARG(ARG'left);
	for i in 0 to control_msb loop
	    if control(i) = '1' then
		temp := rtype'(others => sign_bit);
		if 2**i <= result_msb then
		    temp(result_msb - 2**i downto 0) := 
					result(result_msb downto 2**i);
		end if;
		result := temp;
	    end if;
	end loop;
	return result;
    end;




    function CONV_INTEGER(ARG: INTEGER) return INTEGER is
    begin
	return ARG;
    end;

    function CONV_INTEGER(ARG: UNSIGNED) return INTEGER is
	variable result: INTEGER;
	variable tmp: STD_ULOGIC;
	-- synopsys built_in SYN_UNSIGNED_TO_INTEGER
    begin
	-- synopsys synthesis_off
	assert ARG'length <= 31
	    report "ARG is too large in CONV_INTEGER"
	    severity FAILURE;
	result := 0;
	for i in ARG'range loop
	    result := result * 2;
	    tmp := tbl_BINARY(ARG(i));
	    if tmp = '1' then
		result := result + 1;
	    elsif tmp = 'X' then
		assert false
		report "CONV_INTEGER: There is an 'U'|'X'|'W'|'Z'|'-' in an arithmetic operand, and it has been converted to 0."
		severity WARNING;
	    end if;
	end loop;
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_INTEGER(ARG: SIGNED) return INTEGER is
	variable result: INTEGER;
	variable tmp: STD_ULOGIC;
	-- synopsys built_in SYN_SIGNED_TO_INTEGER
    begin
	-- synopsys synthesis_off
	assert ARG'length <= 32
	    report "ARG is too large in CONV_INTEGER"
	    severity FAILURE;
	result := 0;
	for i in ARG'range loop
	    if i /= ARG'left then
		result := result * 2;
	        tmp := tbl_BINARY(ARG(i));
	        if tmp = '1' then
		    result := result + 1;
	        elsif tmp = 'X' then
		    assert false
		    report "CONV_INTEGER: There is an 'U'|'X'|'W'|'Z'|'-' in an arithmetic operand, and it has been converted to 0."
		    severity WARNING;
	        end if;
	    end if;
	end loop;
	tmp := MAKE_BINARY(ARG(ARG'left));
	if tmp = '1' then
	    if ARG'length = 32 then
		result := (result - 2**30) - 2**30;
	    else
		result := result - (2 ** (ARG'length-1));
	    end if;
	end if;
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_INTEGER(ARG: STD_ULOGIC) return SMALL_INT is
	variable tmp: STD_ULOGIC;
	-- synopsys built_in SYN_FEED_THRU
    begin
	-- synopsys synthesis_off
	tmp := tbl_BINARY(ARG);
	if tmp = '1' then
	    return 1;
	elsif tmp = 'X' then
	    assert false
	    report "CONV_INTEGER: There is an 'U'|'X'|'W'|'Z'|'-' in an arithmetic operand, and it has been converted to 0."
	    severity WARNING;
	    return 0;
	else
	    return 0;
	end if;
	-- synopsys synthesis_on
    end;


    -- convert an integer to a unsigned STD_ULOGIC_VECTOR
    function CONV_UNSIGNED(ARG: INTEGER; SIZE: INTEGER) return UNSIGNED is
	variable result: UNSIGNED(SIZE-1 downto 0);
	variable temp: integer;
	-- synopsys built_in SYN_INTEGER_TO_UNSIGNED
    begin
	-- synopsys synthesis_off
	temp := ARG;
	for i in 0 to SIZE-1 loop
	    if (temp mod 2) = 1 then
		result(i) := '1';
	    else 
		result(i) := '0';
	    end if;
	    if temp > 0 then
		temp := temp / 2;
	    else
		temp := (temp - 1) / 2; -- simulate ASR
	    end if;
	end loop;
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_UNSIGNED(ARG: UNSIGNED; SIZE: INTEGER) return UNSIGNED is
	constant msb: INTEGER := min(ARG'length, SIZE) - 1;
	subtype rtype is UNSIGNED (SIZE-1 downto 0);
	variable new_bounds: UNSIGNED (ARG'length-1 downto 0);
	variable result: rtype;
	-- synopsys built_in SYN_ZERO_EXTEND
    begin
	-- synopsys synthesis_off
	new_bounds := MAKE_BINARY(ARG);
	if (new_bounds(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := rtype'(others => '0');
	result(msb downto 0) := new_bounds(msb downto 0);
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_UNSIGNED(ARG: SIGNED; SIZE: INTEGER) return UNSIGNED is
	constant msb: INTEGER := min(ARG'length, SIZE) - 1;
	subtype rtype is UNSIGNED (SIZE-1 downto 0);
	variable new_bounds: UNSIGNED (ARG'length-1 downto 0);
	variable result: rtype;
	-- synopsys built_in SYN_SIGN_EXTEND
    begin
	-- synopsys synthesis_off
	new_bounds := MAKE_BINARY(ARG);
	if (new_bounds(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := rtype'(others => new_bounds(new_bounds'left));
	result(msb downto 0) := new_bounds(msb downto 0);
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_UNSIGNED(ARG: STD_ULOGIC; SIZE: INTEGER) return UNSIGNED is
	subtype rtype is UNSIGNED (SIZE-1 downto 0);
	variable result: rtype;
	-- synopsys built_in SYN_ZERO_EXTEND
    begin
	-- synopsys synthesis_off
	result := rtype'(others => '0');
	result(0) := MAKE_BINARY(ARG);
	if (result(0) = 'X') then
	    result := rtype'(others => 'X');
	end if;
	return result;
	-- synopsys synthesis_on
    end;


    -- convert an integer to a 2's complement STD_ULOGIC_VECTOR
    function CONV_SIGNED(ARG: INTEGER; SIZE: INTEGER) return SIGNED is
	variable result: SIGNED (SIZE-1 downto 0);
	variable temp: integer;
	-- synopsys built_in SYN_INTEGER_TO_SIGNED
    begin
	-- synopsys synthesis_off
	temp := ARG;
	for i in 0 to SIZE-1 loop
	    if (temp mod 2) = 1 then
		result(i) := '1';
	    else 
		result(i) := '0';
	    end if;
	    if temp > 0 then
		temp := temp / 2;
	    else
		temp := (temp - 1) / 2; -- simulate ASR
	    end if;
	end loop;
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_SIGNED(ARG: UNSIGNED; SIZE: INTEGER) return SIGNED is
	constant msb: INTEGER := min(ARG'length, SIZE) - 1;
	subtype rtype is SIGNED (SIZE-1 downto 0);
	variable new_bounds : SIGNED (ARG'length-1 downto 0);
	variable result: rtype;
	-- synopsys built_in SYN_ZERO_EXTEND
    begin
	-- synopsys synthesis_off
	new_bounds := MAKE_BINARY(ARG);
	if (new_bounds(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := rtype'(others => '0');
	result(msb downto 0) := new_bounds(msb downto 0);
	return result;
	-- synopsys synthesis_on
    end;

    function CONV_SIGNED(ARG: SIGNED; SIZE: INTEGER) return SIGNED is
	constant msb: INTEGER := min(ARG'length, SIZE) - 1;
	subtype rtype is SIGNED (SIZE-1 downto 0);
	variable new_bounds : SIGNED (ARG'length-1 downto 0);
	variable result: rtype;
	-- synopsys built_in SYN_SIGN_EXTEND
    begin
	-- synopsys synthesis_off
	new_bounds := MAKE_BINARY(ARG);
	if (new_bounds(0) = 'X') then
	    result := rtype'(others => 'X');
	    return result;
	end if;
	result := rtype'(others => new_bounds(new_bounds'left));
	result(msb downto 0) := new_bounds(msb downto 0);
	return result;
	-- synopsys synthesis_on
    end;


    function CONV_SIGNED(ARG: STD_ULOGIC; SIZE: INTEGER) return SIGNED is
	subtype rtype is SIGNED (SIZE-1 downto 0);
	variable result: rtype;
	-- synopsys built_in SYN_ZERO_EXTEND
    begin
	-- synopsys synthesis_off
	result := rtype'(others => '0');
	result(0) := MAKE_BINARY(ARG);
	if (result(0) = 'X') then
	    result := rtype'(others => 'X');
	end if;
	return result;
	-- synopsys synthesis_on
    end;


    -- convert an integer to an STD_LOGIC_VECTOR
    function CONV_STD_LOGIC_VECTOR(ARG: INTEGER; SIZE: INTEGER) return STD_LOGIC_VECTOR is
	variable result: STD_LOGIC_VECTOR (SIZE-1 downto 0);
	variable temp: integer;
	-- synopsys built_in SYN_INTEGER_TO_SIGNED
    begin
	-- synopsys synthesis_off
	temp := ARG;
	for i in 0 to SIZE-1 loop
	    if (temp mod 2) = 1 then
		result(i) := '1';
	    else 
		result(i) := '0';
	    end if;
	    if temp > 0 then
		temp := temp / 2;
	    else
		temp := (temp - 1) / 2; -- simulate ASR
	    end if;
	end loop;
	return result;
	-- synopsys synthesis_on
    end;