syntax error..dont know why model sim is showing this while compiling: vhdl

[rambleach]

this is a program for 2^n to n priority encoder

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Code VHDL - [expand]
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library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
 
entity encoder is
  generic (n:positive);
  port (a:in std_logic_vector(2**n-1 downto 0);
    z:out std_logic_vector(n-1 downto 0);
    v:out std_logic);
  end entity encoder;
 
  architecture exm1 of encoder is
  begin
    prc:process(a) is
   
    v<='0';
  z<=(others=>'0');
  for k in a'range loop
  if a(k)='1' then
  z<=std_logic_vector(to_unsigned (k,n));
  v<='1';
  exit;
end if;
end loop;
end process prc;
end architecture exm1 ;

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** Error: C:/Modeltech_pe_edu_10.1a/examples/encoder.vhd(16): near "v": syntax error
** Error: C:/Modeltech_pe_edu_10.1a/examples/encoder.vhd(18): near "in": expecting ':'

these are compilation errors i cannot find anything wrong ..plzz help!! i

 

[TrickyDicky]

remove the "is" after process
and you need a "begin" before the code inside the process

 

[rambleach]

thanks a bunch

 

[lucbra]

And as a general remark: try to use more specific names. Using v, z, a, n ... is not recommended.

 

[rambleach]

the "is " seems to be optional , it didn't matter if i removed it or not !


@lucbra what do you mean by specific terms , can you please explain,.

 

[K-J]

You forgot the 'begin' statement after the process declaration

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Code VHDL - [expand]
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prc:process(a) is
begin

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Kevin Jennings

 

[permute]

yes "is" is optional. I use it because it matches the rest of VHDL's style (eg, if ... then, for ... loop, component ... is, entity ... is, with ... select, when ... else). But it doesn't actually matter. IIRC some editors have process macros that don't include them.

single letter variables are often expected to be index or temporary values in most coding styles. it isn't a syntax error, but you'll make people unhappy with cryptic names.

 

[lucbra]

single letter variables are often expected to be index or temporary values in most coding styles. it isn't a syntax error, but you'll make people unhappy with cryptic names.

Permute answered this question perfectly.

i.e. in stead of

generic (
   n  : positive)

you could write:

generic
   Width : positive)

makes you code readable.