Amstrad CPC464 Command Reference

Variables, notation etc

Special characters

& or &H	prefix for hex constant
&X	prefix for binary constant
:	seperates statements on same line
#	prefix for stream director
Strings	0-255 characters long, may be appended by +, $=string
Integer	-32768...32767, %=integer
Real	nine digits precision, !=real

Command reference

ABS(x)

returns the absolute value of x

AFTER delay, timer GOSUB line

Invoke subroutine at line after a delay of delay 1/50ths of a second using timer timer

ASC(x$)

returns ASCII value of x$

ATN(x)

returns arctan(x)

AUTO linenumber, increment

Generates line numbers as you type in programs. Starting at linenumber and incrementing by increment.

BIN$(number, digits)

returns a string of length digits for the binary representation of number

BORDER colour1, colour2

Changes border colour. If two colours are specified alternates at the rate determined by the SPEED INK command

CALL address, list of parameters

call an external sub-routine from basic

CAT

Reads device and lists all files found.
$ - BASIC program
% - Protected BASIC program
* - an ASCII text file
& - a binary file

CHAIN

Loads program from device replacing program in memory.

CHAIN MERGE

Merges file from device with program in memory

CHR$(x)

returns character equivalent of number x

CINT(x)

converts x to rounded integer.

CLEAR

clears all variables and files

CLG

clears graphics screen

CLOSEIN

close cassette input file

CLOSEOUT

close output file

CLS#x

clears screen window to paper colour

CONT

continue program execution after a BREAK, STOP or END

COS(x)

returns cos(x) in radians

CREAL

converts number to a real number

DATA

DATA list of constants

DEF FN name(parameters)=expression

Should be written outside the main execution loop. e.g. DEF FNinterest(principle)=1.14*principle.

DEFINT, DEFSTR, DEFREAL

Define a range of default data types. The variable is set according to the first letter of the name. e.g. DEFINT I-N. defines all variables beginning I-N as INT

DEG

sets results of radial functions to returns degrees rather than radians.

DELETE number range

Deletes a range of line numbers.

DI

Disable interrupts, other than BREAK, until re-enabled with EI or the return from an interrupt GOSUB

DIM

allocate space for arrays e.g. DIM b$(5)

DRAW x,y,i

DRAW from current graphics cursor position to x,y using masked ink colour i

DRAWR x,y,i

DRAW from current graphics position to relative x,y with masked ink colour i

EDIT linenumber

edits a line

EI

enable interrupts - after DI command

END

end a program

ENT envelopenumber, envelopesections

varies tone of a sound

ENV envelopenumber, envelopesections

varies volume of a sound

EOF

Tests to see if the cassette input is at the end of the file. Returns -1 (true) at the end, otherwise 0 (false).

ERASE arrayname

Erases memory allocated to an array

ERR

Variable used in error handling.

ERL

Variable used in error handling.

ERROR integer

Take error action with a given error number.

EVERY time, timer, GOSUB line

Calls line at interval time, four timers are available (0..3)

EXP(number)

calculates e^number

FIX(number)

Leaves integer expression, rounds fraction to zero

FOR start TO end STEP size

Standard FOR..NEXT loop

FRE(0)

Gives free memory available to BASIC, FRE(&&) forces a 'garbage collection' before returning a value.

GOSUB line

Standard GOSUB

GOTO line

Standard GOTO

HEX$ (decimal number)

Converts decimal to hex

HIMEM

Gives highest byte of memory.

IF expression THEN expression ELSE expression

Standard IF..THEN..ELSE, can also have IF exp GOTO line ELSE exp

INK number, colour

Changes INK number to colour. Number of INKs available graphics mode dependent.

INKEY number

Scans keyboard, result is numeric code.

INKEY$

Reads a key from the keyboard, results in ASCII character or empty string.

INP port

Reads from I/O port.

INPUT #stream,&prompt&;variable1,variable2...

INPUT from a stream, giving a 'prompt'.

INTRS(integer, string1, string2)

Searches string1 for the first occurence of string2 starting from the optional integer start point.

INT(number)

Rounds to nearest lower integer.

JOY(joystick number)

Reads from joystick number (0 or 1), result is bit significant.

Bit	Decimal	Function
0	1	Up
1	2	Down
2	4	Left
3	8	Right
4	16	Fire 2
5	32	Fire 1

KEY keynumber,string

Associates a function key with a string definition. Keynumber is in the range 128-159.

KEY DEF

Defines what a particular key returns.

LEFT$ (src$, n)

Returns leftmost n characters of string src$

LEN(string)

Returns length of string

LET variable=expression

Associates variable with value of expression.

LINE INPUT #stream, quotedstring, string variable

Accepts a line of input from #stream, printing quotedstring as a prompt, leaving result in the string variable.

LIST numberrange, stream

Lists program in number range, where number range can be n-m, -m or n-. Can be redirected to a window.

LOAD filename, address

Loads a program into memory. LOAD filename used for BASIC programs and LOAD filename, address for binary files.

LOCATE #stream, x,y

Moves text cursor in specified stream to position x,y

LOG(n)

Returns natural logarithm of n

LOG10(n)

Returns base 10 log of n

LOWER$(string)

Returns a new string with all lower case characters.

MAX (a,b,c,d,e)

Returns max value in the specified list.

MEMORY &address

Sets the highest byte available to BASIC

MERGE filename

Merges a file into the program in memory.

MID$ (string, start, number)

Returns number characters from string starting from start

MIN a,b,c,d,e,f etc

Returns least value in the list.

MODE number

Changed screen mode.

MOVE x,y

moves graphics cursor to x,y

MOVER x,y

moves graphics cursor x,y relative to it's current position.

NEW

Delete current program and variables.

NEXT variable

Delimits FOR statement, the variable name is not needed.

ON integer expression GOSUB list of line numbers

integer expression is evaluated and the program branches to corresponding line number. e.g. if expression results in 2 the 2nd line number isused for the GOSUB

ON integer expression GOTO list of line numbers

integer expression is evaluated and the program jumps to corresponding line number. e.g. if expression results in 2 the 2nd line number isused for the GOTO

ON BREAK GOSUB line

Jumps to a subroutine at line when a program's execution is stopped.

ON BREAK STOP

Issued from the commandline prevents an ON BREAK GOSUB from working when the program is run.

ON ERROR GOTO line

if an error occurs GOTO line.

ON SQ (channel) GOSUB line

Enable an interrupt for when there is a free slow in te given sound queue. 1 for channel A, 2 for channel B, 3 for channel C

OPENIN "filename"

Opens a file for reading.

OPENOUT "filename"

Opens a file for writing to.

ORIGIN x,y

Sets the start point for the graphics cursor. Using origin x,y,left,right,top,bottom sets a new window and the origin within the window.

OUT &port,integer

Sends integer to the specified port.

PAPER

Sets the background colour.

PEEK &addr

Returns contents of an address.

PEN

Sets the pen colour on the specified screen.

PI

3.14159265

PLOT x,y,colour

Moves graphics cursor and plots colour from current position.

PLOTR

Moves graphics cursor and plots colour.

POKE &addr, value

Pokes value into address.

POS(#stream)

Returns x-coord for screen streams, returns carriage position for printer where 1 is left margin.

PRINT #screen, string

Prints.

RAD

sets radians mode

RANDOMIZE

sets initial value for randon number generator.

READ

Fetches data from a DATA statement.

RELEASE sound channel

When a sound is placed in a sound queue, it may contain a 'hold' state, this command releases the channel.

REM

Remark.

REMAIN(timer)

Disables the specified delay timer.

RENUM new line, from old line, increment

Renumbers BASIC program.

RESTORE line number

Restores back to a data statement. Defaults to first.

RESUME

Allows program to continue after an ON ERROR GOTO event.

RETURN

returns from GOSUB

RIGHT$(source, number)

Returns rightmost number of characters from source.

RND

random number.

ROUND number, places

Rounds number to places.

RUN <string>

Runs a program.

RUN <line number>

Run program in memory from line number.

SAVE filename, type, binary

Saves program.
Type is
,A - ASCII
,P - protects file
,B - saves as binary
binary parameters are start, lenght, entry point.

SGN(number)

Returns sign of number.

SIN(angle)

Sine of angle.

SOUND channel status, tone period, duration, volume, volume envelope, tone envelope, noise period

SPACE$(number)

Create string containing number of spaces.

SPEED INK time1, time2

INK and BORDER allow two colours to be associated with each Ink. This command alternated between the two.

SPEED KEY delay, repeat

SPEED WRITE integer

Changes the baud rate of the cassette interface. 1 is 2000 baud, 0 is 1000 baud

SQ channel

Checks number of free entries in the queue for a given channel

SQR(number)

Square root of a number.

STOP

Stops program execution

STR$(number)

Converts number to a string.

STRING$(integer, character)

Returns a string integer digits long consisting of the character.

SYMBOL

Redefines the representation of a character.

SYMBOL AFTER

sets number of user definable characters. Default is 240 leaving 16 characters available.

TAG #stream

Redirects text sent to the given stream to the graphics cursor.

TAGOFF #stream

Cancels TAG for the stream

TAN

Tangent of an angle.

TEST(x,y)

Returns colour at x,y

TESTR(x-off, y-off)

Returns ink at x offset, y offset

TIME

Reports elapsed time since system turned on.

TRON

Traces exection of a program

TROFF

Cancels TRON

UNT(&addr)

Converts unsigned 16bit integer to a value in range -32768 to +32767

UPPER$(string)

Converts string to uppercase.

VAL

Returns numeric evaluation of string.

VPOS(#stream)

Returns the vertical position of the text cursor.

WAIT port, mask, inversion

Suspends BASIC until i/o port returns a particular value. Value read is X-OR'd with inversion and then ANDed with mask until result is non-zero.

WEND

WHILE...WEND loop.

WHILE

WHILE condtion ... expressions ... WEND

WIDTH

Specifies printer width

WINDOW #stream, left,right,top,bottom

Sets a text window for a given stream.

WINDOW SWAP stream1, stream2

Swaps text windows.

WRITE #stream, list

Writes to a stream.

XPOS

Gives x position of graphics cursor.

YPOS

Gives x position of graphics cursor.

ZONE integer

Changes width of print zone.

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from: Classic 8-bit Computers