jens/vhdl
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

- added integer shift amount (sa)

Browse Source 
with positive value for left shift and negaitve values for right shift
- removed shift_left port
Committed on the Free edition of March Hare Software CVSNT Server.
Upgrade to CVS Suite for more features and support:
http://march-hare.com/cvsnt/


git-svn-id: http://moon:8086/svn/vhdl/trunk@799 cc03376c-175c-47c8-b038-4cd826a8556b
This commit is contained in:
jens
2010-03-18 20:18:25 +00:00
parent e84c9c287e
commit 6409d43d38
1 changed files with 10 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/emac/src/shifter.vhd
+10 -11
View File
@@ -16,8 +16,7 @@ ENTITY shifter IS
(
rst : in STD_LOGIC;
clk : in STD_LOGIC;
shift_left : in STD_LOGIC;
sa : in unsigned(NextExpBaseTwo(data_width/aggregate_size)-1 downto 0);
sa : in integer;
din_vld : in STD_LOGIC;
din : in unsigned(data_width-1 downto 0);
dout_vld : out STD_LOGIC;
@@ -29,29 +28,29 @@ END shifter;
ARCHITECTURE behavior OF shifter IS
constant num_rounds : natural := NextExpBaseTwo(data_width/aggregate_size);
subtype sa_rnd_t is signed(num_rounds-1 downto 0);
subtype word_t is unsigned(data_width-1 downto 0);
type word_array_t is array (0 to num_rounds) of word_t;
signal rot_data : word_array_t;
signal sa_rnd : unsigned (num_rounds-1 downto 0);
signal sa_rnd : sa_rnd_t;
subtype sa_rnd_t is unsigned(num_rounds-1 downto 0);
type sa_rnd_array_t is array (0 to num_rounds) of sa_rnd_t;
signal sa_rnd_pipe : sa_rnd_array_t;
signal dout_vld_pipe : unsigned(0 to num_rounds);
--------------------------------------------------------------------------
function rot_stage(x : unsigned; en : std_logic; stage_num : natural; size : natural) return unsigned is
function rol_stage(x : unsigned; en : std_logic; stage_num : natural; size : natural) return unsigned is
variable result : unsigned(x'range);
constant sa : natural := (2**stage_num) * size;
begin
if en = '1' then
result := x(sa-1 downto 0) & x(x'left downto sa);
result := x(x'left-sa downto 0) & x(x'left downto x'length-sa);
else
result := x;
end if;
return result;
end rot_stage;
end rol_stage;
--------------------------------------------------------------------------
begin
@@ -66,10 +65,10 @@ begin
gen_rotate_right:
for stage in 0 to num_rounds-1 generate
begin
rot_data(stage+1) <= rot_stage(rot_data(stage), sa_rnd(stage), stage, aggregate_size);
rot_data(stage+1) <= rol_stage(rot_data(stage), sa_rnd(stage), stage, aggregate_size);
end generate;
sa_rnd <= not sa + 1 when shift_left = '1' else sa;
sa_rnd <= to_signed(sa, num_rounds);
dout <= rot_data(num_rounds);
dout_vld <= din_vld;
@@ -81,7 +80,7 @@ if do_pipelined = true generate
begin
rot_data(0) <= din;
sa_rnd_pipe(0) <= not sa + 1 when shift_left = '1' else sa;
sa_rnd_pipe(0) <= to_signed(sa, num_rounds);
dout_vld_pipe(0) <= din_vld;
gen_rotate_right:
@@ -96,7 +95,7 @@ gen_rotate_right:
dout_vld_pipe(stage+1) <= dout_vld_pipe(stage);
if dout_vld_pipe(stage) = '1' then
sa_rnd_pipe(stage+1) <= sa_rnd_pipe(stage);
rot_data(stage+1) <= rot_stage(rot_data(stage), sa_rnd_pipe(stage)(stage), stage, aggregate_size);
rot_data(stage+1) <= rol_stage(rot_data(stage), sa_rnd_pipe(stage)(stage), stage, aggregate_size);
end if;
end if;
end if;