While loop problems

[seoken]

Problem: The Altera compiler thinks that it will take more than 10k iterations to complete this segment of code. I am not seeing how it would take more than a maximum of 36... I have not been coding in vhdl for all that long so I will more than accept any answer that should be obvious.


Code description: This should take an integer in the range of 0 to 9999 and separate the digits into their bcd compatible segments...

doConv:	process (big_dec)
	variable temp,tOne,tTen,tHun,tTho: integer := 0;
	begin
		if(big_dec > 9999) then
			temp := 9999;
		else
			temp := big_dec;
		end if;
		
		while temp >= 1000 loop
			temp := temp - 1000;
			tTho := tTho + 1;
		end loop;
		
		while temp >= 100 loop
			temp := temp - 100;
			tHun := tHun + 1;
		end loop;
		
		while temp >= 10 loop
			temp := temp - 10;
			tTen := tTen + 1;
		end loop;
		
		while temp >= 1 loop
			temp := temp - 1;
			tOne := tOne + 1;
		end loop;
		
		ones <= tOne;
		tens <= tTen;
		hund <= tHun;
		thou <= tTho;
	end process;

 

[JohnDuq]

You have the knowledge that after the first while loop that temp will be less than 1000, and after the second while loop temp will be less than 100. I expect Altera isn't that smart so it is setting itself up to deal with a very large number on the last while loop (what is your integer definition -16 bit, 32 bit?).

One solution might be to assign an eight bit variable that you set equal to temp after the second while loop. Then use that variable for the following while loops.

John