COMMODORE PET BASIC QUICK REFERENCE CARD
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(adapted from Commodore 64 Programmer's Reference Guide from Project 64)
Link: Project 64 Page
Type Name Range
Real XY +/- 1.70141183E+38
Integer XY% +/- 32767
String XY$ 0 to 255 characters
X is a letter (A-Z), Y is a letter or number (0-9). Variable names
can be more than 2 characters, but only the first two are recognized.
Single Dimension XY(5)
Arrays of up to eleven elements (subscripts 0-10) can be used
where needed. Arrays with more than eleven elements need to be
Time TI Display the system clock in jiffy ticks
TI$ Display/Set the system time in 24 hour clock
format i.e. TI$="030012" ("HHMMSS")
I/O Status ST Tape/File access status number.
Pi (¼, Pi symbol) Value of Pi.
4.0 BASIC Disk Status DS Reads Current Disk Error Condition from dev 8
DS$ Reads Complete Error Condition to string
"##, ERR TXT, Track, Sect"
ALGEBRAIC OPERATORS RELATIONAL AND LOGICAL OPERATORS
= Assigns value to variable = Equal
- Negation < > Not Equal To
^ Exponentiation < Less Than
* Multiplication > Greater Than
/ Division <= Less Than or Equal To
+ Addition >= Greater Than or Equal To
- Substraction NOT Logical "Not"
AND Logical "And"
OR Logical "Or"
Expression equals 1 if true, 0 if false
LOAD"NAME" Loads a program from tape
SAVE"NAME" Saves a program on tape
LOAD"NAME",8 Loads a program from disk
SAVE"NAME",8 Saves a program to disk
VERIFY"NAME" Verifies that program was SAVEd without errors
RUN Executes a program
RUN xxx Executes program starting at line xxx
STOP Halts execution
END Ends execution
CONT Continues program execution from line where
program was halted
PEEK(X) Returns contents of memory location X
POKE X,Y Changes contents of location X to value Y
SYS xxxxx Jumps to execute a machine language program,
starting at xxxxx
WAIT X,Y,Z Program waits until contents of location X,
when EORed with Z and ANDed with Y, is nonzero.
USR(X) Passes value of X to a machine language subroutine can also
return value from m/l subroutine (is used like a function
EDITING AND FORMATTING COMMANDS
LIST Lists entire program
LIST A-B Lists from line A to line B
REM Message Comment message can be listed but is ignored during
TAB(X) Used in PRINT statement. Spaces X positions on screen
SPC(X) PRINTs X blanks on line
POS(X) Returns current cursor position
EDITING AND FORMATTING KEYS
CLR/HOME Positions cursor to left corner of screen
SHIFT+CLR/HOME Clears screen and places cursor in "Home" position
SHIFT+INST/DEL Inserts space at current cursor position
INST/DEL Deletes character at current cursor position
CTRL When used with numeric color key, selects text color.
May be used in PRINT statement.
CRSR keys Moves cursor up, down, left, right on screen
SHIFT Access Graphics characters in upper case/graphics mode
and upper case characters in upper/lower case mode.
ARRAYS AND STRINGS
DIM A(X,Y,Z) Sets maximum subscripts for A; reserves space for
(X+1)*(Y+1)*(Z+1) elements starting at A(0,0,0)
LEN(X$) Returns number of characters in X$
STR$(X) Returns numeric value of X, converted to a string
VAL(X$) Returns numeric value of X$, up to first
CHR$(X) Returns ASCII character whose code is X
ASC(X$) Returns ASCII code for first character of X$
LEFT$(A$,X) Returns leftmost X characters of A$
RIGHT$(A$,X) Returns rightmost X characters of A$
MID$(A$,X,Y) Returns Y characters of A$ starting at character X
INPUT A$ or A PRINTs "?" on screen and waits for user to enter
a string or value
INPUT "ABC";A PRINTs message and waits for user to enter value.
Can also INPUT A$
GET A$ or A Waits for user to type one-character value; no
DATA A,"B",C Initializes a set of values that can be used by
READ A$ or A Assigns next DATA value to A$ or A
RESTORE Resets data pointer to start READing the DATA list again
PRINT"A= ";A PRINTs string "A=" and value of A
";" suppresses spaces - "," tabs data to next field
GOTO X Branches to line X
IF A=1 TO 10 IF assertion is true THEN execute following part of
statement. IF false, execute next line number
FOR A=1 TO 10 STEP 2 Executes all statements between FOR and
corresponding NEXT, with A going from 1 to 10
by 2. Step size is 1 unless specified
NEXT A Defines end of loop. A is optional
GOSUB 2000 Branches to subtoutine starting at line 2000
RETURN Marks end of subroutine. Returns to statement following
most recent GOSUB
ON X GOTO A,B Branches to Xth line number on list. If X=1 branches
to A, etc.
ON X GOSUB A,B Branches to subroutine at Xth line number in list
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