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microwatt/cr_file.vhdl

61 lines
1.6 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library work;
use work.common.all;
entity cr_file is
port(
clk : in std_logic;
d_in : in Decode2ToCrFileType;
d_out : out CrFileToDecode2Type;
w_in : in WritebackToCrFileType
);
end entity cr_file;
architecture behaviour of cr_file is
signal crs : std_ulogic_vector(31 downto 0) := (others => '0');
signal crs_updated : std_ulogic_vector(31 downto 0) := (others => '0');
begin
cr_create_0: process(all)
variable hi, lo : integer := 0;
variable cr_tmp : std_ulogic_vector(31 downto 0) := (others => '0');
begin
cr_tmp := crs;
for i in 0 to 7 loop
if w_in.write_cr_mask(i) = '1' then
lo := i*4;
hi := lo + 3;
cr_tmp(hi downto lo) := w_in.write_cr_data(hi downto lo);
end if;
end loop;
crs_updated <= cr_tmp;
end process;
-- synchronous writes
cr_write_0: process(clk)
begin
if rising_edge(clk) then
if w_in.write_cr_enable = '1' then
report "Writing " & to_hstring(w_in.write_cr_data) & " to CR mask " & to_hstring(w_in.write_cr_mask);
crs <= crs_updated;
end if;
end if;
end process;
-- asynchronous reads
cr_read_0: process(all)
begin
-- just return the entire CR to make mfcrf easier for now
if d_in.read = '1' then
report "Reading CR " & to_hstring(crs_updated);
end if;
d_out.read_cr_data <= crs_updated;
end process;
end architecture behaviour;