shall I reuse a variable/signal or not?

[walala]

Dear all,

Here is a fragment of my code... t1, t2, t3, t4, temp1, temp2, temp3,
temp4 are my temporary variables... Y0, Y7, Y1, Y6 are the actual
result I want to output...

I want to know if I can re-use t1, t2 and temp1 and temp2, that's to
say, don't use t3, t4, temp3 and temp4? What will be the impact of
that change to my circuit?

Less storage memory? Less adders?

Can anybody tell me?

Thanks a lot,

-Walala
----------------------------------------------------------------------------


t1:=91*ZZ(0)(count2)+118*ZZ(2)(count2)+91*ZZ(4)(count2)+49*ZZ(6)(count2);

t2:=126*ZZ(1)(count2)+106*ZZ(3)(count2)+71*ZZ(5)(count2)+25*ZZ(7)(count2);
temp1:=t1+t2;
temp2:=t1-t2;
Y0<=temp1(23 downto 16);
Y7<=temp2(23 downto 16);


t3:=91*ZZ(0)(count2)+49*ZZ(2)(count2)-91*ZZ(4)(count2)-118*ZZ(6)(count2);

t4:=106*ZZ(1)(count2)-25*ZZ(3)(count2)-126*ZZ(5)(count2)-71*ZZ(7)(count2);
temp3:=t3+t4;
temp4:=t3-t4;
Y1<=temp1(23 downto 16);
Y6<=temp2(23 downto 16);

 

[Jon]

Hi Walala,
There really is no hardware impact of reusing the variables but for
clarity and ease of debug keep them seperate.

Jon

mizhael@yahoo.com (walala) wrote in message news:<6f348bd1.0309120954.5292af3b@posting.google.com>...

Dear all,

Here is a fragment of my code... t1, t2, t3, t4, temp1, temp2, temp3,
temp4 are my temporary variables... Y0, Y7, Y1, Y6 are the actual
result I want to output...

I want to know if I can re-use t1, t2 and temp1 and temp2, that's to
say, don't use t3, t4, temp3 and temp4? What will be the impact of
that change to my circuit?

Less storage memory? Less adders?

Can anybody tell me?

Thanks a lot,

-Walala
----------------------------------------------------------------------------


t1:=91*ZZ(0)(count2)+118*ZZ(2)(count2)+91*ZZ(4)(count2)+49*ZZ(6)(count2);

t2:=126*ZZ(1)(count2)+106*ZZ(3)(count2)+71*ZZ(5)(count2)+25*ZZ(7)(count2);
temp1:=t1+t2;
temp2:=t1-t2;
Y0<=temp1(23 downto 16);
Y7<=temp2(23 downto 16);


t3:=91*ZZ(0)(count2)+49*ZZ(2)(count2)-91*ZZ(4)(count2)-118*ZZ(6)(count2);

t4:=106*ZZ(1)(count2)-25*ZZ(3)(count2)-126*ZZ(5)(count2)-71*ZZ(7)(count2);
temp3:=t3+t4;
temp4:=t3-t4;
Y1<=temp1(23 downto 16);
Y6<=temp2(23 downto 16);