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microwatt/writeback.vhdl

81 lines
2.5 KiB
VHDL

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