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- minor improvements for load/store shifter

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git-svn-id: http://moon:8086/svn/vhdl/trunk@430 cc03376c-175c-47c8-b038-4cd826a8556b
This commit is contained in:
jens
2009-04-15 13:21:39 +00:00
parent 1c5db27de0
commit a3c4ba6e82
1 changed files with 75 additions and 79 deletions
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lib/CPUs/MIPS/src/core/mips_types.vhd
+75 -79
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@@ -264,7 +264,7 @@ package mips_types is
end record;
type cop0_ctrl_out_t is record
RE : STD_LOGIC;
EB : STD_LOGIC;
exc_inject : STD_LOGIC;
exc_commit : STD_LOGIC;
exc_pending : STD_LOGIC;
@@ -454,56 +454,53 @@ package body mips_types is
function store_be(va : unsigned(1 downto 0); be_src, word2_en, word4_en, align_left, bypass : std_logic) return unsigned is
variable result : unsigned(3 downto 0);
begin
if bypass = '1' then
result := (3 downto 0 => be_src);
elsif word2_en = '1' then
case va is
when "00" | "01" =>
result := "00" & be_src & be_src;
when "10" | "11" =>
result := be_src & be_src & "00";
when others =>
result := "0000";
end case;
elsif word4_en = '1' then
case va is
when "00" =>
result := "000" & be_src;
when "01" =>
result := "00" & be_src & '0';
when "10" =>
result := '0' & be_src & "00";
when "11" =>
result := be_src & "000";
when others =>
result := "0000";
end case;
elsif align_left = '1' then
case va is
when "00" =>
result := be_src & be_src & be_src & be_src;
when "01" =>
result := be_src & be_src & be_src & '0';
when "10" =>
result := be_src & be_src & "00";
when "11" =>
result := be_src & "000";
when others =>
result := "0000";
end case;
else
case va is
when "00" =>
result := "000" & be_src;
when "01" =>
result := "00" & be_src & be_src;
when "10" =>
result := '0' & be_src & be_src & be_src;
when "11" =>
result := be_src & be_src & be_src & be_src;
when others =>
result := "0000";
end case;
result := (3 downto 0 => be_src);
if bypass = '0' then
if word2_en = '1' then
case va is
when "00" =>
result := "00" & be_src & be_src;
when "10" =>
result := be_src & be_src & "00";
when others => null;
end case;
elsif word4_en = '1' then
case va is
when "00" =>
result := "000" & be_src;
when "01" =>
result := "00" & be_src & '0';
when "10" =>
result := '0' & be_src & "00";
when "11" =>
result := be_src & "000";
when others => null;
end case;
elsif align_left = '1' then
case va is
when "00" =>
result := be_src & be_src & be_src & be_src;
when "01" =>
result := be_src & be_src & be_src & '0';
when "10" =>
result := be_src & be_src & "00";
when "11" =>
result := be_src & "000";
when others => null;
end case;
else
case va is
when "00" =>
result := "000" & be_src;
when "01" =>
result := "00" & be_src & be_src;
when "10" =>
result := '0' & be_src & be_src & be_src;
when "11" =>
result := be_src & be_src & be_src & be_src;
when others => null;
end case;
end if;
end if;
return result;
@@ -539,34 +536,33 @@ package body mips_types is
function load_be(va : unsigned(1 downto 0); align_left, bypass : std_logic) return unsigned is
variable result : unsigned(3 downto 0);
begin
if bypass = '1' then
result := (3 downto 0 => '1');
elsif align_left = '1' then
case va is
when "00" =>
result := "1000";
when "01" =>
result := "1100";
when "10" =>
result := "1110";
when "11" =>
result := "1111";
when others =>
result := "0000";
end case;
else
case va is
when "00" =>
result := "1111";
when "01" =>
result := "0111";
when "10" =>
result := "0011";
when "11" =>
result := "0001";
when others =>
result := "0000";
end case;
result := (3 downto 0 => '1');
if bypass = '0' then
if align_left = '1' then
case va is
when "00" =>
result := "1000";
when "01" =>
result := "1100";
when "10" =>
result := "1110";
when "11" =>
result := "1111";
when others => null;
end case;
else
case va is
when "00" =>
result := "1111";
when "01" =>
result := "0111";
when "10" =>
result := "0011";
when "11" =>
result := "0001";
when others => null;
end case;
end if;
end if;
return result;