|
| 新闻出处：21ic
发布时间： 2007-11-13 |
|
zhang_44 发布于 2007-11-10 20:35:00
需要在一个时钟周期内（125MHz）完成，我想进行并行比较，没找到例子，自己写了一个，思路就是1和2比，较大的一个和3比，再得到一个和4比，依次类推。时序仿真结果不太稳定，最大值的位置应该在0-9内，但是结果经常出现10-15，不知道错在哪儿。另外有没有更好的办法能推荐一下，谢谢。
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity max19_10_comb is
port(
clock:in std_logic;
data0,data1,data2,data3,data4,data5,data6,data7:in std_logic_vector(18 downto 0);
data8,data9:in std_logic_vector(18 downto 0);
result_value:out std_logic_vector(18 downto 0);
result_index:out std_logic_vector(3 downto 0)
);
end max19_10_comb;
architecture beha of max19_10_comb is
signal index0:std_logic_vector(3 downto 0):="0000";
signal index1:std_logic_vector(3 downto 0):="0001";
signal index2:std_logic_vector(3 downto 0):="0010";
signal index3:std_logic_vector(3 downto 0):="0011";
signal index4:std_logic_vector(3 downto 0):="0100";
signal index5:std_logic_vector(3 downto 0):="0101";
signal index6:std_logic_vector(3 downto 0):="0110";
signal index7:std_logic_vector(3 downto 0):="0111";
signal index8:std_logic_vector(3 downto 0):="1000";
signal index9:std_logic_vector(3 downto 0):="1001";
signal result01,result02,result03,result04,result05,result06,result07:std_logic_vector(18 downto 0);
signal result08,result09:std_logic_vector(18 downto 0);
signal index01,index02,index03,index04,index05,index06,index07:std_logic_vector(3 downto 0);
signal index08,index09:std_logic_vector(3 downto 0);
begin
process(data0,data1,data2,data3,data4,data5,data6,data7,data8,data9,result01,result02,result03,result04,result05,result06,result07,result08,result09,index01,index02,index03,index04,index05,index06,index07,index08,index09)
begin
if data0 > data1 then
result01 <= data0;
index01 <= index0;
else
result01 <= data1;
index01 <= index1;
end if;
if result01 > data2 then
result02 <= result01;
index02 <= index01;
else
result02 <= data2;
index02 <= index2;
end if;
if result02 > data3 then
result03 <= result02;
index03 <= index02;
else
result03 <= data3;
index03 <= index3;
end if;
if result03 > data4 then
result04 <= result03;
index04 <= index03;
else
result04 <= data4;
index04 <= index4;
end if;
if result04 > data5 then
result05 <= result04;
index05 <= index04;
else
result05 <= data5;
index05 <= index5;
end if;
if result05 > data6 then
result06 <= result05;
index06 <= index05;
else
result06 <= data6;
index06 <= index6;
end if;
if result06 > data7 then
result07 <= result06;
index07 <= index06;
else
result07 <= data7;
index07 <= index7;
end if;
if result07 > data8 then
result08 <= result07;
index08 <= index07;
else
result08 <= data8;
index08 <= index8;
end if;
if result08 > data9 then
result09 <= result08;
index09 <= index08;
else
result09 <= data9;
index09 <= index9;
end if;
end process;
process(clock)
begin
if clock'EVENT and clock = '1' then
result_value <= result09;
result_index <= index09;
end if;
end process;
end beha;
jzt369 发布于 2007-11-11 19:12:00
没有尝试过！组合电路比较复杂吧，如果不影响实时性的话，可以多次比较
zhang123 发布于 2007-11-13 13:36:00
这个显然不是一次比较了。较大的一个和3比，是第二次比较过程。
|
| 【关闭】 【打印】 |
|
|
|
 |
相关专题 |
|
|
|
