article.txt

Increase the speed of your BASIC programs 
by 10 to 45 percent with 

FASTER 64


By Anthony Wood 


Faster 64 is a utility for the Commodore 64 that 
analyzes the use of variables in a BASIC pro- 
gram while it runs. It tells you how often each 
variable in the program is accessed. By defin- 
ing your most often used variables first, BASIC does 
not have to search as far for them, thus speeding up your 
program. For some programs, this speed increase can 
be considerable. 

Faster 64 is a machine language program. Since it is 
slow and inconvenient to use a BASIC program to POKE 
in a machine language program, we have created a spe- 
cial ML listing of Faster 64. To enter Faster 64, refer 
to the Flankspeed instructions on page 94. Once entered 
and SAVEd you need only enter 'LOAD "FASTER 
64", 8, 1' (tape users, 'LOAD "FASTER 64", 1,1') when 
you wish to load the program. To initialize it, you also 
have to type 'SYS 49152'. This should be done after you 
first LOAD it or after you press RUN STOP/RESTORE. 
After you key in the enclosed program, Faster 64, you 
should save it before you run it. Once you have saved 
it, LOAD it and type SYS 49152, and you should see 
the message "Faster 64 working." 

USING FASTER 64 

Load Faster 64 and initialize it. When you see the mes- 
sage "Faster 64 working," enter the following line: 

Q=0:A=0:A(1)=A(2)+A(3):Z$="FRED" 

<RETURN> 

The following should appear: 
A() 3 ,Q 1, A 1,Z$ 1 

This means the array A was referenced 3 times and 
the variables Q, A, and Z$ were each referenced 1 time. 
The variables referenced the most are listed first. 

Key in this short program to test Faster 64 some more: 

NEW 

10 DIM A(20) 

20 FOR Y=l TO 20 

30 A(Y)=A(Y)+1 

40 NEXT 

RUN it. You should get the message: 



Y 41, A() 40 



This means that the array A( ) was referenced 40 times, 
and the variable Y 41 times. Notice that a FOR-NEXT 
loop only references its index once. This is because the 
FOR-NEXT loop stores the address of its index variable. 
It does not have to keep looking it up. It will, however, 
look up the index in every loop if you enter 'NEXT Y' 
instead of just 'NEXT.' 

You should be aware that the variable TI will not work 
with Faster 64; it causes a syntax error. 

To use Faster 64 on one of your programs, load Fast- 
er 64 and initialize it. Note that you might have to enter 
"NEW" after you load Faster 64, to prevent the "out of 
memory" error. This is a bug in the Commodore BASIC 
ROM. Now load your program. Run your program all 
the way through. After your program is finished, its vari- 
ables will be listed in numerical order. Suppose that you 
run your program, and you get the following display 
from Faster 64: 

X 2131, Z 511, P() 200, FQ154, X$ 100, 
D 2 

To initialize the variables in the correct order, you 
would enter a line at the beginning of your program like 
this: 

1 DIM P(100),F(100) 

2 X=0:Z=0:X$="":D=0 

This puts your variables in the most efficient order. No- 
tice that the arrays are on a separate line. 

You should look out for certain exceptions. For ex- 
ample, suppose you find out that the variable A$ is ref- 
erenced 4000 times. It might not be best to define it first, 
if it is not at a place in your program where speed is 
important. For example, suppose A$ appears in this line: 

1000 GET A$:IFA$OCHR$(13)THEN1000 

You can see that AS is in a loop waiting for a return. 
Since it is used in a wait loop, you can define A$ last 
because speed is not important— defining it first would 
just slow down the search for more critical variables. □ 
SEE PROGRAM LISTING ON PAGE 106