The Difference between the two processes

[Digit0001]

Hi

Can someone tell me the difference between the two processes?

	process(A)
		variable start : bit :='0';
		begin
			Start :='0';
			For i in 0 to 3 loop
				start := start or A(i);
			end loop;
			x <= Start;
	end process;

	process(A)
		variable start : bit_vector(4 downto 0);
		begin
			start(0) :='0';
			For i in 0 to 3 loop
				start(i+1) := start(i) or A(i);
			end loop;
			x <= start(4);
	end process;

P.S

 

[TrickyDicky]

There is no difference. They both just OR all of the bits in A.

All of that code could be replaced with

x <= or_reduce(A);

 

[alexan_e]

From what i see these two give the same result, the first one uses a 1 bit start which stores the new result in each value of the loop,
the second one has a 4bit vector which stores the result to the bit on the left.
I don't know if there will be any difference in the gates used after fitting.

Alex