title: 硬件编程语言的部分程序实现
tags: 硬件编程语言
编程语言
7人投票表决器
1、利用全加器实现
library ieee;
use ieee.std_logic_1164.all;
entity vote7 is port(
a,b,c,d,e,f,g:in std_logic;
pass:out std_logic);
architecture one of vote7 is
component f_adder port(
ain,bin,cin:in std_logic;
sum,cout:out std_logic);
end component;
signal b1,c1,a2,b2,c2:std_logic;
begin
u1:f_adder port map(ain=>a,bin=>b1,cin=>c1,cout=>a2,sum=>open);
u2 : f_adder port map(ain=>a2,bin=>b2,cin=>c2,cout=>pass,sum=>open);
u3 : f_adder port map(ain=>b,bin=>c,cin=>d,cout=>b2,sum=>b1);
u4 : f_adder port map(ain=>e,bin=>f,cin=>g,cout=>c2,sum=>c1);
end one;
2、直接实现
LIBRARY ieee;
USE ieee.Std_logic_1164.ALL;
USE ieee.Std_logic_unsigned.ALL; --运算操作符
ENTITY vote7 IS
PORT(
datain : IN Std_logic_vector(6 DOWNTO 0);
termcnt : OUT Std_logic);
END vote7;
ARCHITECTURE v1 OF vote7 IS
BEGIN
main_proc : PROCESS(datain)
variable tsum:integer range 0 to 7;
BEGIN
tsum := 0;
FOR i IN datain'Range LOOP
IF datain(i) = '1' THEN
tsum := tsum+1;
END IF;
END LOOP;
if tsum>=4 then
termcnt<='1';
else
termcnt<='0';
end if;
END PROCESS;
END v1;
4选1数据选择器
USE ieee.std_logic_1164.all
ENTITY mux4 IS
PORT (i0,i1,i2,i3,a,b :IN STD_LOGIC);
q :OUT STD_LOGIC);
END mux4
ARCHOITECTUR OF mux4 IS
SIGNAL sel :INTEGER;
BEGIN
WITH sel SELECT
q <= i0 WHEN 0,
i1 WHEN 1,
i2 WHEN 2,
i3 WHEN 3,
'X' WHEN OTHERS;
sel <= 0 WHEN a = '0' AND b = '0' ELSE
1 WHEN a = '1' AND b = '0' ELSE
2 WHEN a = '0' AND b = '1' ELSE
3 WHEN a = '1' AND b = '1' ELSE
4;
END;