Question

我编写了一个代码来读取文本并将相同的文本写入另一个文本文件，我想将从输入文本中读取的每个字符转换为相应的二进制值。阅读和书写文本完美有效，但问题是它只显示与文本中第一个字符对应的值。请告诉我我在做错的地方。这是我的代码：

 library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use std.textio.all;
use IEEE.NUMERIC_STD.ALL;

entity asconvbin is
    Port ( clk : in  STD_LOGIC;
           d : out  STD_LOGIC_VECTOR(7 downto 0));

end asconvbin;

architecture Behavioral of asconvbin is

begin
process(clk)
 variable OUTLINE : LINE;
      file FILEOUT : TEXT is OUT "outputfile.txt";
      --Input variables
            variable inline:line;
            variable char:character; 
            variable end_of_line:boolean;
            file myfile:text is "myfile.txt";
        variable k:integer;
begin
if rising_edge(clk) then

    while not endfile(myfile) loop
       readline(myfile,inline);     
         k:=inline'high;

        end_of_line := true;
        while end_of_line loop
         read(inline,char,end_of_line);

for i in k downto 0 loop

if char='A' then d<="01000000";
elsif char='B' then d<="01000001";
elsif char='C' then d<="01000010";
elsif char='D' then d<="01000011";
elsif char='E' then d<="01000100";
elsif char='F' then d<="01000101";
elsif char='G' then d<="01000110";
elsif char='H' then d<="01000111";
elsif char='I' then d<="01001000";
elsif char='J' then d<="01001001";
elsif char='K' then d<="01001010";
elsif char='L' then d<="01001011";
elsif char='M' then d<="01001100";
elsif char='N' then d<="01001101";
elsif char='O' then d<="01001110";
elsif char='P' then d<="01001111";
elsif char='Q' then d<="01010000";
elsif char='R' then d<="01010001";
elsif char='S' then d<="01010010";
elsif char='T' then d<="01010011";
elsif char='U' then d<="01010100";
elsif char='V' then d<="01010101";
elsif char='W' then d<="01010110";
elsif char='X' then d<="01010111";
elsif char='Y' then d<="01011000";
elsif char='Z' then d<="01011001";
else null;

             end if;
             k:=k-1;
end loop;

     if end_of_line then 
            WRITE(OUTLINE,char);
          end if;
    end loop;
end loop;
WRITELINE(FILEOUT, OUTLINE); 

end if;
end process;

end Behavioral;

Answer 1

d仅输出第一个字符值的原因是k 在for i in k downto 0 loop中使用k := k-1递减，从而产生在k中，输入文件中的第二个字符为-1，然后是范围 for i in -1 downto 0 loop，这是一个空范围，从而导致循环被跳过，因此没有后续分配给d。代码熟了：

while not endfile(myfile) loop
  readline(myfile, inline);
  k := inline'high;
  ...
  while end_of_line loop
    ...
    for i in k downto 0 loop
      if char = 'A' then d    <= "01000000";
      ...
      end if;
      k := k-1;
    end loop;
    ...
  end loop;
end loop;

将char转换为std_logic_vector的另一种方法是：

d <= std_logic_vector(to_unsigned(character'pos(char), d'length));

仅显示与从文件读取的第一个字符对应的值

1 个答案: