Problems Compiling in ModelSim

Afkar O. (afkarsosman) OP (Company: nanyang polytechnic) 2017-01-25 04:14 #4877353

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Hi,

I'm having some problems compiling my codes, Im trying to do a 4 bit
adder and im confused as to why my codes cant compile and always giving
me error on my "4bitaddertb" codes:

"No feasible entries for infix operator "=".
"Type error resolving infix expression "=" as type 
std.STANDARD.BOOLEAN."

anyone have any idea on where am i going wrong?

thanks.

Attached files:

4bitadder.vhd (1.9 KB) | highlighted code
4bitaddertb.vhd (2.68 KB) | highlighted code
fulladder.vhd (303 Bytes) | highlighted code
halfadder.vhd (281 Bytes) | highlighted code

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Lothar M. (lkmiller) Moderator (Company: Titel) 2017-01-25 09:20 #4877458

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> and always giving me error on my "4bitaddertb" codes:
Related to which line of code?

Beside that minor problem you have a big problem in your code:

   if clk="1" then
       A_S <= "0000";
   elsif (clk='1' AND clk'event) then
       A_S <= A_S + "0001";
   end if;

Here A_S will be always "0000", except for 0ps (as long as a rising edge 
lasts) it will be "0001".

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Kest Guest 2017-01-25 11:05 #4877577

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Lothar M. wrote:
> Related to which line of code?

 if clk="1" then

here it is:

 if clk='1' then