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microwatt/writeback.vhdl

95 lines
2.3 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
signal e : Execute2ToWritebackType;
signal l : Loadstore2ToWritebackType;
signal m : MultiplyToWritebackType;
signal w_tmp : WritebackToRegisterFileType;
signal c_tmp : WritebackToCrFileType;
begin
writeback_0: process(clk)
begin
if rising_edge(clk) then
e <= e_in;
l <= l_in;
m <= m_in;
end if;
end process;
w_out <= w_tmp;
c_out <= c_tmp;
complete_out <= '1' when e.valid or l.valid or m.valid else '0';
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.valid;
y := "" & l.valid;
z := "" & m.valid;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1;
x := "" & e.write_enable;
y := "" & l.write_enable;
z := "" & m.write_reg_enable;
assert (to_integer(unsigned(x)) + to_integer(unsigned(y)) + to_integer(unsigned(z))) <= 1;
assert not(e.write_cr_enable = '1' and m.write_cr_enable = '1');
w_tmp <= WritebackToRegisterFileInit;
c_tmp <= WritebackToCrFileInit;
if e.write_enable = '1' then
w_tmp.write_reg <= e.write_reg;
w_tmp.write_data <= e.write_data;
w_tmp.write_enable <= '1';
end if;
if e.write_cr_enable = '1' then
c_tmp.write_cr_enable <= '1';
c_tmp.write_cr_mask <= e.write_cr_mask;
c_tmp.write_cr_data <= e.write_cr_data;
end if;
if l.write_enable = '1' then
w_tmp.write_reg <= l.write_reg;
w_tmp.write_data <= l.write_data;
w_tmp.write_enable <= '1';
end if;
if m.write_reg_enable = '1' then
w_tmp.write_enable <= '1';
w_tmp.write_reg <= m.write_reg_nr;
w_tmp.write_data <= m.write_reg_data;
end if;
if m.write_cr_enable = '1' then
c_tmp.write_cr_enable <= '1';
c_tmp.write_cr_mask <= m.write_cr_mask;
c_tmp.write_cr_data <= m.write_cr_data;
end if;
end process;
end;