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95 lines
2.3 KiB
VHDL
95 lines
2.3 KiB
VHDL
library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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library work;
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use work.common.all;
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entity writeback is
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port (
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clk : in std_ulogic;
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e_in : in Execute2ToWritebackType;
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l_in : in Loadstore2ToWritebackType;
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m_in : in MultiplyToWritebackType;
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w_out : out WritebackToRegisterFileType;
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c_out : out WritebackToCrFileType;
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complete_out : out std_ulogic
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);
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end entity writeback;
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architecture behaviour of writeback is
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signal e : Execute2ToWritebackType;
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signal l : Loadstore2ToWritebackType;
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signal m : MultiplyToWritebackType;
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signal w_tmp : WritebackToRegisterFileType;
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signal c_tmp : WritebackToCrFileType;
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begin
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writeback_0: process(clk)
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begin
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if rising_edge(clk) then
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e <= e_in;
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l <= l_in;
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m <= m_in;
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end if;
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end process;
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w_out <= w_tmp;
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c_out <= c_tmp;
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complete_out <= '1' when e.valid or l.valid or m.valid else '0';
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writeback_1: process(all)
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variable x: std_ulogic_vector(0 downto 0);
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variable y: std_ulogic_vector(0 downto 0);
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variable z: std_ulogic_vector(0 downto 0);
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begin
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x := "" & e.valid;
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y := "" & l.valid;
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z := "" & m.valid;
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assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1;
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x := "" & e.write_enable;
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y := "" & l.write_enable;
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z := "" & m.write_reg_enable;
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assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1;
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assert not(e.write_cr_enable = '1' and m.write_cr_enable = '1');
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w_tmp <= WritebackToRegisterFileInit;
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c_tmp <= WritebackToCrFileInit;
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if e.write_enable = '1' then
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w_tmp.write_reg <= e.write_reg;
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w_tmp.write_data <= e.write_data;
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w_tmp.write_enable <= '1';
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end if;
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if e.write_cr_enable = '1' then
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c_tmp.write_cr_enable <= '1';
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c_tmp.write_cr_mask <= e.write_cr_mask;
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c_tmp.write_cr_data <= e.write_cr_data;
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end if;
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if l.write_enable = '1' then
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w_tmp.write_reg <= l.write_reg;
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w_tmp.write_data <= l.write_data;
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w_tmp.write_enable <= '1';
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end if;
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if m.write_reg_enable = '1' then
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w_tmp.write_enable <= '1';
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w_tmp.write_reg <= m.write_reg_nr;
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w_tmp.write_data <= m.write_reg_data;
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end if;
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if m.write_cr_enable = '1' then
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c_tmp.write_cr_enable <= '1';
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c_tmp.write_cr_mask <= m.write_cr_mask;
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c_tmp.write_cr_data <= m.write_cr_data;
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end if;
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end process;
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end;
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