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Line 25... |
-- shift_nothing, shift_left_unsigned,
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-- shift_nothing, shift_left_unsigned,
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-- shift_left_signed, shift_right_unsigned);
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-- shift_left_signed, shift_right_unsigned);
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begin
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begin
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shift_proc: process(value, shift_amount, shift_func) --barrel shifter unit
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shift_proc: process(value, shift_amount, shift_func) --barrel shifter unit
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variable shift1, shift2, shift4,
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variable shift1L, shift2L, shift4L, shift8L, shift16 :
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shift8, shift16 : std_logic_vector(31 downto 0);
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std_logic_vector(31 downto 0);
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variable shift1R, shift2R, shift4R, shift8R :
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std_logic_vector(31 downto 0);
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variable fills : std_logic_vector(31 downto 16);
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variable fills : std_logic_vector(31 downto 16);
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variable go_right : std_logic;
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variable go_right : std_logic;
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begin
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begin
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if shift_func = shift_right_unsigned or shift_func = shift_right_signed then
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if shift_func = shift_right_unsigned or shift_func = shift_right_signed then
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go_right := '1';
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go_right := '1';
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| Line 42... |
Line 44... |
else
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else
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fills := "0000000000000000";
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fills := "0000000000000000";
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end if;
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end if;
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if go_right = '0' then --shift left
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if go_right = '0' then --shift left
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if shift_amount(0) = '1' then
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if shift_amount(0) = '1' then
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shift1 := value(30 downto 0) & '0';
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shift1L := value(30 downto 0) & '0';
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else
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else
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shift1 := value;
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shift1L := value;
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end if;
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end if;
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if shift_amount(1) = '1' then
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if shift_amount(1) = '1' then
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shift2 := shift1(29 downto 0) & "00";
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shift2L := shift1L(29 downto 0) & "00";
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else
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else
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shift2 := shift1;
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shift2L := shift1L;
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end if;
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end if;
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if shift_amount(2) = '1' then
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if shift_amount(2) = '1' then
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shift4 := shift2(27 downto 0) & "0000";
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shift4L := shift2L(27 downto 0) & "0000";
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else
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else
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shift4 := shift2;
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shift4L := shift2L;
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end if;
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end if;
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if shift_amount(3) = '1' then
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if shift_amount(3) = '1' then
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shift8 := shift4(23 downto 0) & "00000000";
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shift8L := shift4L(23 downto 0) & "00000000";
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else
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else
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shift8 := shift4;
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shift8L := shift4L;
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end if;
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end if;
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if shift_amount(4) = '1' then
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if shift_amount(4) = '1' then
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shift16 := shift8(15 downto 0) & ZERO(15 downto 0);
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shift16 := shift8L(15 downto 0) & ZERO(15 downto 0);
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else
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else
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shift16 := shift8;
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shift16 := shift8L;
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end if;
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end if;
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else --shift right
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else --shift right
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if shift_amount(0) = '1' then
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if shift_amount(0) = '1' then
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shift1 := fills(31) & value(31 downto 1);
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shift1R := fills(31) & value(31 downto 1);
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else
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else
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shift1 := value;
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shift1R := value;
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end if;
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end if;
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if shift_amount(1) = '1' then
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if shift_amount(1) = '1' then
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shift2 := fills(31 downto 30) & shift1(31 downto 2);
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shift2R := fills(31 downto 30) & shift1R(31 downto 2);
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else
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else
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shift2 := shift1;
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shift2R := shift1R;
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end if;
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end if;
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if shift_amount(2) = '1' then
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if shift_amount(2) = '1' then
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shift4 := fills(31 downto 28) & shift2(31 downto 4);
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shift4R := fills(31 downto 28) & shift2R(31 downto 4);
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else
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else
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shift4 := shift2;
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shift4R := shift2R;
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end if;
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end if;
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if shift_amount(3) = '1' then
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if shift_amount(3) = '1' then
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shift8 := fills(31 downto 24) & shift4(31 downto 8);
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shift8R := fills(31 downto 24) & shift4R(31 downto 8);
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else
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else
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shift8 := shift4;
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shift8R := shift4R;
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end if;
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end if;
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if shift_amount(4) = '1' then
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if shift_amount(4) = '1' then
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shift16 := fills(31 downto 16) & shift8(31 downto 16);
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shift16 := fills(31 downto 16) & shift8R(31 downto 16);
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else
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else
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shift16 := shift8;
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shift16 := shift8R;
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end if;
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end if;
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end if; --shift_dir
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end if; --shift_dir
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if shift_func = shift_nothing then
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if shift_func = shift_nothing then
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c_shift <= ZERO;
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c_shift <= ZERO;
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else
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else
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