Atari 800

MEMORY
CONSERVATION
11
ADVANCED PROGRAMMING
TECHNIQUES
This section includes hints on increasing programming efficiency, conserving
memory, and combining machine language programs with Atari BASIC pro-
grams. This section does not include an instruction set for the 6502 micro-
processor chip nor does it give instructions on programming in machine
language. An additional purchase of the Atari Assembler Editor cartridge* and
a careful study of Atari's Assembler Editor Manual are strongly recommended .
These hints give ways of conserving memory . Some ofthese methods make pro-
grams less readable and harder to modify, but there are cases where this is
necessary due to memory limitations.
1. In many small computers, eliminating blank spaces between words and
characters as they are typed into the keyboard will save memory . This is not
true of the ATARI Personal Computer System, which removes extra spaces.
Statements are always displayed the same regardless of how many spaces
were used on program entry. Spaces should be used Gust as in typing on a
conventional typewriter) between successive keywords and between
keywords and variable names. Here is an example:
10 IF A
5 THEN PRINT A
Note the space between IF and A and between THEN and PRINT. In most
cases, a statement will be interpreted correctly by the computer even if all
spaces are left out, but this is not always true. Use conventional spacing.
2. Each new line number represents the beginning of what is called a new
"logical line". Each logical line takes 6 bytes of " overhead ", whether it is
used to full capacity or not. Adding an additional BASIC statement by using a
colon (:) to separate each pair of statements on the same line takes only 3
bytes.
*Available late 1980.
Advanced Programming Techniques 61