MiSTer MultiComp

Port of Grant Searle's MultiComp to the MiSTer.

Ported by Cyril Venditti and Fred VanEijk.

Updated by S0urceror to use MiSTer image files, use all 4 machine types and have the MiSTer UART connected to serial interface 2 of the core. The latter allows to use the core remotely.

Using the MiSTer Serial Terminal/Console

Connection Methods

USB: Connect the console port from the MiSTer FPGA to your computer using a USB cable.
Network: Use SSH to connect to the MiSTer FPGA if you have a Wireless or Ethernet connection.
USB/Serial cable: For more information see the Serial Port section of the Altair8800_MiSTer repository: https://github.com/MiSTer-devel/Altair8800_MiSTer

Setting Up the Connection

For UART/Serial with PuTTY

Connect at 115200 baud, 8 bits, no parity to the COM port.

USB to serial cable connection

User Port - extra USB 3.1A style connector on MiSTer

USB	P7	Name	PIN	Mister	emu wire
1	+5V	+5V
2	2	TX	SDA	AH9	USER_IO[1]
3	1	RX	SCL	AG11	USER_IO[0]
4	GND	GND
5	8	DSR	IO10	AF15	USER_IO[5]
6	7	DTR	IO11	AG16	USER_IO[4]
7	6	CTS	IO12	AH11	USER_IO[3]
8	5	RTS	IO13	AH12	USER_IO[2]
9	10	IO6	IO8	AF17	USER_IO[6]
10	Shield	Shield

FT232 USB to serial cable

wire	name	mister usb IO port
Red	5V	N/C
Black	GND	GND
White	RXD	2
Green	TXD	3
Yellow	RTS	7
Blue	CTS	8

For SSH with PuTTY

Connect to the ip address of your MiSTer fpga.

Linux command line to establish the connection to the core

Identify the UART device:
- Usually mapped to /dev/ttyS1 or /dev/ttyUSB0
- Use this command to help identify the correct device:
```
dmesg | grep tty
```
Access the serial terminal:
- Use screen or minicom
- Example command with screen:
```
screen /dev/ttyS1 115200
```
- Replace /dev/ttyS1 with the correct device identifier
- Change 115200 to the appropriate baud rate if different
Enable Flow Control:
- Use stty
```
stty -F /dev/ttyS1 crtscts
```
- Replace /dev/ttyS1 with the correct device identifier
- This is done before the screen command

Additional Information

For more details on console connection, refer to the official MiSTer documentation: MiSTer Console Connection Guide

The MiSTer OSD allows the access to five machines

Z80 CP/M

You can now use both an external SDCard in the secondary slot and/or select the image file within MiSTer. Whatever you like.

Formatting the SD Card and Installing CP/M

Note this procedure has to be performed from a tty terminal as descibed above.

Formatting the Drive

Load the Intel-HEX dump of the FORMAT program into memory by copying the contents of FORM128.HEX (for 128MB SD card utilization) into the terminal window.
The FORMAT program will reside at memory address $5000 when loaded. To start the formatting process, execute the program by typing G5000 and pressing ENTER.
You will see the following message:

CP/M Formatter by G. Searle 2012

After a few seconds, the formatting process will display:

ABCDEFGHIJKLMNOP
Formatting complete

Each drive is 8MB, so a 128MB SD card will have drives labeled A: to P:.

Installing CP/M

CP/M is installed on the first track of the disk. When booted, the first track is read into memory and executed. To install CP/M, follow these steps:

Load the Intel-HEX dump of CP/M by copying the contents of CPM22.HEX into the terminal window (this takes about 10 seconds).
Load the Intel-HEX dump of the CBIOS by copying the contents of CBIOS128.HEX (for 128MB total drive space) into the terminal window (this takes about 3 seconds).
Load the Intel-HEX dump of PUTSYS by copying the contents of PUTSYS.HEX into the terminal window.

The PUTSYS program also resides at memory address $5000. To transfer CP/M and CBIOS to the disk, execute PUTSYS by typing G5000 and pressing ENTER. You will see:

CP/M System Transfer by G. Searle 2012
System transfer complete

At this point, CP/M is installed and ready for boot. You can now proceed with installing applications.

Boot CP/M from image file

Note that currently the DOWNLOAD.COM program is not working reliably (we hope to fix this in the future). To get around the issues with DOWNLOAD.COM we have added the cpm image file and some Python based utilities, thus being able to get a working and custamizable CP/M sytem up and running.

In the CPM-sd-image directory, you will find a zip file that contains a cmp.img file that can be copied to the /media/fat/games/MultipComp directory. This file can be used to boot CP/M without the SD card. It contains the structure for disks A thru P with A having the DOWNLOAD program and other utilities available. Use this as a strating point to place CP/M applications on the image. See the Installing Applications section at http://searle.x10host.com/Multicomp/cpm/fpgaCPM.html#InstallingCPM.

Note the process for this is mostly described in PART 2 - Using the Windows packager program. The packager program is in windowsApp. Again, this process requires the use of the tty terminal not the console, as you will be pasting the file data into the terminal.

We have also added a zip file in the CPM-sd-image directory with a set of application pre installed. See cpm-apps.zip. This file can also be copied to the /media/fat/games/MultipComp directory and mounted. It contains 5 drives A,C,D,E, and F where A still only has the DOWNLOAD program and the other drives contain the following. The cpm.zip file contains just the basic utilities described in the CPM-sd-image directory.

C:	D:	E:	F:
0_FILES.TXT	0_GAMES	0_OLDUTILS	0_NEWUTILS
1_BDS_TINY_C	1_MUMATHSIMP	1_F80M80BASIC	1_ROMS
2_APL	2_CROSSTALK	2_AZTEC_C_106D	2_ZSYSTEM
3_JANUS_ADA15	3_QTERM43	3_TPASCAL3	3_MICROPRO
4_MS_COBOL	4_CLINK	4_DXFORTH401	4_MULTIPLAN
5_PILOT	5_SUPERSFTUTIL	5_PLI14	5_DBASEII
6_SYSLIB	6_RCPM	6_ALGOLM	6_DWG_APPS
7_BBC BASIC	7_DDTZ SOURCES	7_SUPERCALC	8_MICROSHELL

Note the use of user numbers here i.e. 0_, 1_ etc..
(Not all the applications were tested to run, so you are on your own)

The applications were obtained from the Obsolescence Guaranteed site.

Included in the CPM-sd-image directory are also some python scripts to initialize/build the image for the CP/M disks. Along with a script in the transient packages directory that can extract the .COM files from the package (note this was used to provide some content to build the cpm.img file provided in CPM-sd-image directory).

To use the Python scripts we recommend using Visual Studio Code and opening the MultiComp_MiSTer directory as its project location. Them just run the Python scripts from within Visual Studio Code.

Other useful links.

For convenience you can use the Multicomp FPGA - CP/M Demo Disk from Obsolescence Guaranteed: http://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk

After you have flashed the CP/M Demo Disk to the SD Card you will have to use the secondary SD Card on the MiSTer on the I/O Board: https://github.com/MiSTer-devel/Wiki_MiSTer/wiki/IO-Board

Using CP/M - from Grant Searle website: http://searle.x10host.com/Multicomp/cpm/fpgaCPM.html

DeRamp - This website focuses on early personal computers from the mid 70s into the early 80s. Here you'll find resources for restoring and maintaining many of the great computers and peripherals from this era, in addition it has a Downloads section where you can find the bits for many applications. https://deramp.com/

Z80 Basic

SGN, INT, ABS ,USR, FRE, INP, POS, SQR, RND ,LOG, EXP, COS, SIN, TAN, ATN, PEEK ,DEEK ,LEN, STR$, VAL ,ASC, CHR$ ,LEFT$, RIGHT$, MID$, END, FOR, NEXT, DATA, INPUT, DIM, READ, LET, GOTO, RUN, IF, RESTORE, GOSUB, RETURN, REM, STOP, OUT, ON, NULL, WAIT, DEF, POKE, DOKE, LINES, CLS, WIDTH, MONITOR, PRINT, CONT, LIST, CLEAR, NEW, TAB, TO, FN, SPC, THEN, NOT, STEP, +, -, *, /, ^, AND, OR, >, <, =

PLUS additional implementations here (making it version 4.7b):

HEX$(nn) - convert a SIGNED integer (-32768 to +32767) to a string containing the hex value

BIN$(nn) - convert a SIGNED integer (-32768 to +32767) to a string containing the binary value

&Hnn - interpret the value after the &H as a HEX value (signed 16 bit)

&Bnn - interpret the value after the &B as a BINARY value (signed 16 bit)

6502 Basic - No SD card support (No CSAVE/CLOAD)

END, FOR, NEXT, DATA, INPUT, DIM, READ, LET, GOTO, RUN, IF, RESTORE, GOSUB, RETURN, REM, STOP, ON, NULL, WAIT, DEF, POKE, PRINT, CONT, LIST, CLEAR, NEW, TAB(, TO, FN, SPC(, THEN, NOT, STEP, SGN, INT, ABS, USR, FRE, POS, SQR, RND, LOG, EXP, COS, SIN, TAN, ATN, PEEK, LEN, STR$, VAL, ASC, CHR$, LEFT$, RIGHT$, MID$, +, -, *, /, ^, AND, OR, >, +, <

6809 Basic - No SD card support(No CSAVE/CLOAD)

FOR, GO, REM, ELSE, IF, DATA, PRINT, ON GOSUB, ON GOTO, INPUT, LINE INPUT, END, NEXT, DIM, READ, RUN, RESTORE, RETURN, STOP, POKE, CONT, LIST, CLEAR, NEW, EXEC, TAB, TO, SUB, THEN, NOT, STEP, +, -, *, /, ^, AND, OR, >, =, <, DEL, DEF, LET, RENUM, FN, &, &H, TRON, TROFF, EDIT, SGN, INT, ABS, USR, RND, SIN, PEEK, LEN, STR$, VAL, ASC, CHR$, LEFT$, RIGHT$, MID$, INKEY$, MEM, ATN, COS, TAN, EXP, FIX, LOG, SQR, HEX$, VARPTR, INSTR, STRING$, MID$ (MODIFICATION), POS

http://searle.x10host.com/Multicomp/#BASICKeywords

6809 Camel Forth

A 6809 implementation of Camel Forth

MultiComp OSD Configuration

This section describes the On-Screen Display menu configuration for the MultiComp system, providing control over CPU selection, storage, and communication parameters.

Menu Structure

System Control

Mount *.IMG: Provide the image in the games/Multicomp directory if no image is specified it will attempt to use the secondary SD card
Reset after Mount: Configures system behavior after mounting storage - Options: No, Yes
Reset: System reset function

CPU and ROM Configuration

CPU-ROM Selection:
Z80 with CP/M
Z80 with BASIC
6502 with BASIC
6809 with BASIC
6809 Forth

Communication Settings

Baud Rate:
115200
38400
19200
9600
4800
2400
Serial Port:
Console Port - use the MiSTer console port
User IO Port - use the MiSTer user I/O USB 3.1 port
Flow Control:
None - no hardware flow control
RTS/CTS - enable hardware flow control using RTS/CTS signals

Additional Information

The OSD includes version information and build date tracking. This configuration interface provides comprehensive control over the MultiComp's core functionality, allowing users to switch between different CPU architectures, operating systems, and I/O configurations.

The menu system is designed for straightforward navigation and configuration of the MultiComp's essential features, making it accessible for both basic setup and advanced customization needs.

Troubleshooting

Serial Communication Issues

Only the Z80 supports the external uart at this time
If no response when typing:
- Verify correct baud rate is selected
- Check that the correct serial port is selected (Console vs User IO)
- Try enabling/disabling flow control
- For User IO port, verify cable connections match pinout documentation

Storage Issues

If unable to access CP/M:
Verify Secondary SD card is properly formatted or an image is selected in the OSD
Try toggling "Reset after Mount" option
Once either the secondary SD card is selected or the Image file is selected a complete MiSTer re-start is required to change the selection i.e. it can not be changed with a reset of the core.

System Stability

6809 Basic had known reset issues (inherited from original design) the core was actually being reset but only a warm reset, now it supports a cold or warm reset with a prompt
If system becomes unresponsive:
- Use OSD Reset function
- Try power cycling the MiSTer
- Verify correct CPU-ROM selection for your intended use

Known Limitations

If the DOWNLOAD.COM program has reliability issues in CP/M use a slower baud rate, we have had some sucess at 2400 and 9600 baud, 115200 baud seems to consistantly drop characters even with flow control enabled
6502 and 6809 Basic variants do not support SD card operations (no CSAVE/CLOAD)\

License

Software and VHDL project download link

By downloading these files you must agree to the following: The original copyright owners of ROM contents are respectfully acknowledged. Use of the contents of any file within your own projects is permitted freely, but any publishing of material containing whole or part of any file distributed here, or derived from the work that I have done here will contain an acknowledgment back to myself, Grant Searle, and a link back to this page. Any file published or distributed that contains all or part of any file arom this page must be made available free of charge.

Original Author

Grant Searle

URL

Grant's MULTICOMP pick and mix computer

MiSTer MultiComp BASIC Keywords Reference

Keywords by Category

Mathematical Functions

Keyword	Z80	6502	6809	Description	Usage Example
ABS	✓	✓	✓	Returns absolute value	`X = ABS(-5)`
ATN	✓	✓	✓	Returns arctangent	`A = ATN(1)`
COS	✓	✓	✓	Returns cosine	`C = COS(3.14159/2)`
EXP	✓	✓	✓	Returns e raised to power	`E = EXP(2)`
FIX	-	-	✓	Truncates decimal portion	`F = FIX(3.7)`
INT	✓	✓	✓	Returns integer portion	`I = INT(5.7)`
LOG	✓	✓	✓	Returns natural logarithm	`L = LOG(100)`
SGN	✓	✓	✓	Returns sign of number (-1,0,1)	`S = SGN(-42)`
SIN	✓	✓	✓	Returns sine	`S = SIN(3.14159/2)`
SQR	✓	✓	✓	Returns square root	`R = SQR(16)`
TAN	✓	✓	✓	Returns tangent	`T = TAN(0.785)`

String Functions

Keyword	Z80	6502	6809	Description	Usage Example
ASC	✓	✓	✓	Returns ASCII value of character	`A = ASC("A")`
CHR$	✓	✓	✓	Returns character for ASCII value	`C$ = CHR$(65)`
INSTR	-	-	✓	Searches for substring	`I = INSTR(A$, "FIND")`
LEFT$	✓	✓	✓	Returns leftmost characters	`L$ = LEFT$("HELLO", 2)`
LEN	✓	✓	✓	Returns string length	`L = LEN("TEST")`
MID$	✓	✓	✓	Returns substring	`M$ = MID$("HELLO", 2, 2)`
RIGHT$	✓	✓	✓	Returns rightmost characters	`R$ = RIGHT$("WORLD", 3)`
STR$	✓	✓	✓	Converts number to string	`S$ = STR$(123)`
STRING$	-	-	✓	Creates string of repeated characters	`S$ = STRING$(5, "*")`
VAL	✓	✓	✓	Converts string to number	`V = VAL("123")`

Program Control

Keyword	Z80	6502	6809	Description	Usage Example
CONT	✓	✓	✓	Continues program execution	`CONT`
END	✓	✓	✓	Ends program	`END`
FOR/NEXT	✓	✓	✓	Loop structure	`FOR I=1 TO 10 : PRINT I : NEXT I`
GOSUB	✓	✓	✓	Calls subroutine	`GOSUB 1000`
GOTO	✓	✓	✓	Jumps to line number	`GOTO 100`
IF/THEN	✓	✓	✓	Conditional execution	`IF X=5 THEN PRINT "YES"`
ON GOSUB	-	-	✓	Multiple branch subroutine	`ON X GOSUB 100,200,300`
ON GOTO	-	-	✓	Multiple branch jump	`ON X GOTO 100,200,300`
RETURN	✓	✓	✓	Returns from subroutine	`RETURN`
STOP	✓	✓	✓	Halts program execution	`STOP`

Data and Variables

Keyword	Z80	6502	6809	Description	Usage Example
DATA	✓	✓	✓	Stores program data	`DATA 100,200,"TEXT"`
DEF FN	✓	✓	✓	Defines function	`DEF FNA(X)=X*X+2`
DIM	✓	✓	✓	Declares array dimensions	`DIM A(10),B$(20)`
INPUT	✓	✓	✓	Accepts user input	`INPUT "Name?";N$`
LET	✓	✓	✓	Assigns variable value	`LET A=5` or `A=5`
LINE INPUT	-	-	✓	Inputs entire line	`LINE INPUT "Text?";A$`
READ	✓	✓	✓	Reads DATA values	`READ A,B,C$`
RESTORE	✓	✓	✓	Resets DATA pointer	`RESTORE`

System and Memory

Keyword	Z80	6502	6809	Description	Usage Example
DEEK	✓	-	-	Reads word from memory	`D = DEEK(16384)`
DOKE	✓	-	-	Writes word to memory	`DOKE 16384,12345`
FRE	✓	✓	-	Returns free memory	`F = FRE(0)`
INP	✓	-	-	Reads from I/O port	`I = INP(255)`
MEM	-	-	✓	Returns memory size	`M = MEM`
OUT	✓	-	-	Writes to I/O port	`OUT 255,10`
PEEK	✓	✓	✓	Reads byte from memory	`P = PEEK(16384)`
POKE	✓	✓	✓	Writes byte to memory	`POKE 16384,255`
USR	✓	✓	✓	Calls machine language routine	`U = USR(32768)`
VARPTR	-	-	✓	Returns variable address	`V = VARPTR(A)`

Program Editing

Keyword	Z80	6502	6809	Description	Usage Example
CLEAR	✓	✓	✓	Clears variables	`CLEAR`
CLS	✓	-	-	Clears screen	`CLS`
DEL	-	-	✓	Deletes program lines	`DEL 100-200`
EDIT	-	-	✓	Edits program line	`EDIT 100`
LIST	✓	✓	✓	Lists program	`LIST` or `LIST 100-200`
NEW	✓	✓	✓	Clears program	`NEW`
RENUM	-	-	✓	Renumbers program lines	`RENUM 100,10`
RUN	✓	✓	✓	Executes program	`RUN` or `RUN 100`
TRON/TROFF	-	-	✓	Trace mode on/off	`TRON` or `TROFF`

Z80 BASIC Specific Extensions (v4.7b)

Keyword	Description	Usage Example
HEX$(nn)	Converts signed integer to hex string	`H$ = HEX$(255)`
BIN$(nn)	Converts signed integer to binary string	`B$ = BIN$(15)`
&Hnn	Interprets nn as hexadecimal value	`X = &H1F`
&Bnn	Interprets nn as binary value	`Y = &B1010`

Operators

Operator	Z80	6502	6809	Description	Usage Example
+	✓	✓	✓	Addition	`A = B + C`
-	✓	✓	✓	Subtraction	`X = Y - Z`
*	✓	✓	✓	Multiplication	`P = Q * R`
/	✓	✓	✓	Division	`D = N / 2`
^	✓	✓	✓	Exponentiation	`E = 2 ^ 3`
AND	✓	✓	✓	Logical AND	`IF A>0 AND B<10 THEN...`
OR	✓	✓	✓	Logical OR	`IF X=0 OR Y=0 THEN...`
NOT	✓	✓	✓	Logical NOT	`IF NOT A THEN...`
>	✓	✓	✓	Greater than	`IF X > 10 THEN...`
<	✓	✓	✓	Less than	`IF Y < 5 THEN...`
=	✓	✓	✓	Equal to	`IF A = B THEN...`
&	-	-	✓	Bitwise AND	`R = X & Y`

Notes:

Z80 BASIC is the most commonly used version for CP/M systems
6502 BASIC is a Microsoft BASIC variant
6809 BASIC has the most extensive command set but lacks storage commands
None of the 6502 and 6809 variants support CSAVE/CLOAD operations

Each example shows the most common usage pattern for the command. Many commands have additional optional parameters or alternate syntaxes not shown in these basic examples.

BASIC Programming Examples

A collection of example programs demonstrating various BASIC programming concepts and commands.

Some of these may only run on the 6809.

Number Guessing Game

This program demonstrates input handling, loops, and conditional statements. The computer picks a random number and the player has 10 tries to guess it.

10 REM Number Guessing Game
20 CLS
30 PRINT "Number Guessing Game!"
40 LET N = INT(RND(1) * 100) + 1
50 LET TRIES = 0
60 PRINT "Guess a number between 1 and 100"
70 INPUT "Your guess: "; G
80 LET TRIES = TRIES + 1
90 IF G = N THEN GOTO 150
100 IF G < N THEN PRINT "Too low!"
110 IF G > N THEN PRINT "Too high!"
120 IF TRIES < 10 THEN GOTO 70
130 PRINT "Sorry, you've run out of tries. The number was"; N
140 GOTO 160
150 PRINT "Congratulations! You got it in"; TRIES; "tries!"
160 INPUT "Play again (Y/N)? "; A$
170 IF LEFT$(A$, 1) = "Y" OR LEFT$(A$, 1) = "y" THEN GOTO 40
180 END

Key concepts:

Random number generation
Input validation
Conditional branching
Loop control
String comparison

String Manipulation

This example demonstrates various string operations and functions available in BASIC.

10 REM String Manipulation Demo
20 LET A$ = "BASIC Programming"
30 PRINT "Original string: "; A$
40 PRINT "Length: "; LEN(A$)
50 PRINT "First 5 chars: "; LEFT$(A$, 5)
60 PRINT "Last 7 chars: "; RIGHT$(A$, 7)
70 PRINT "Middle 6 chars: "; MID$(A$, 7, 6)
80 FOR I = 1 TO LEN(A$)
90 PRINT MID$(A$, I, 1);
100 NEXT I
110 PRINT
120 END

Key concepts:

String functions (LEN, LEFT$, RIGHT$, MID$)
Character-by-character processing
String concatenation
FOR/NEXT loops with strings

Math Functions Calculator

A simple calculator program that demonstrates mathematical functions and structured programming using subroutines.

10 REM Math Functions Calculator
20 PRINT "Math Functions Calculator"
30 PRINT "1. Square Root"
40 PRINT "2. Sine"
50 PRINT "3. Cosine"
60 PRINT "4. Tangent"
70 PRINT "5. Exit"
80 INPUT "Choose a function (1-5): "; C
90 IF C = 5 THEN END
100 INPUT "Enter a number: "; N
110 ON C GOSUB 200, 300, 400, 500
120 GOTO 20
200 PRINT "Square root of"; N; "is"; SQR(N)
210 RETURN
300 PRINT "Sine of"; N; "is"; SIN(N)
310 RETURN
400 PRINT "Cosine of"; N; "is"; COS(N)
410 RETURN
500 PRINT "Tangent of"; N; "is"; TAN(N)
510 RETURN

Key concepts:

Subroutines with GOSUB/RETURN
ON GOSUB branching
Mathematical functions
Menu-driven interface

Array Operations

Demonstrates array handling, loops, and basic statistical calculations.

10 REM Array Operations
20 DIM A(10)
30 REM Fill array with numbers
40 FOR I = 1 TO 10
50 LET A(I) = I * 2
60 NEXT I
70 REM Calculate sum and average
80 LET S = 0
90 FOR I = 1 TO 10
100 LET S = S + A(I)
110 NEXT I
120 PRINT "Sum:"; S
130 PRINT "Average:"; S/10
140 REM Find maximum value
150 LET M = A(1)
160 FOR I = 2 TO 10
170 IF A(I) > M THEN LET M = A(I)
180 NEXT I
190 PRINT "Maximum value:"; M
200 END

Key concepts:

Array declaration and initialization
Array traversal
Running sums
Finding maximum values
Basic statistics

Simple Data Management

Shows how to work with DATA statements for storing and accessing program data.

10 REM Simple Data Management
20 DIM N$(5), A(5)
30 FOR I = 1 TO 5
40 READ N$(I), A(I)
50 NEXT I
60 REM Print all records
70 PRINT "Name", "Age"
80 PRINT "----", "---"
90 FOR I = 1 TO 5
100 PRINT N$(I), A(I)
110 NEXT I
120 DATA "John", 25, "Mary", 32, "Bob", 45, "Alice", 28, "Tom", 19
130 END

Key concepts:

DATA statements
READ operations
Parallel arrays
Formatted output
String and numeric arrays

Custom Function Definition

Demonstrates how to create and use user-defined functions.

10 REM Custom Function Demo
20 DEF FNC(X) = 5 * X^2 + 2 * X + 1
30 DEF FNF(X) = (X * 9/5) + 32
40 INPUT "Enter a number: "; N
50 PRINT "Quadratic result:"; FNC(N)
60 PRINT N; "Celsius ="; FNF(N); "Fahrenheit"
70 END

Key concepts:

Function definition with DEF FN
Mathematical expressions
Temperature conversion
Function parameter passing

Each of these examples can be extended or modified to create more complex programs. Note that some BASIC dialects may require slight modifications to these programs depending on the specific implementation.

Forth Language Glossary

Guide to Stack Diagrams

R: = return stack
c = 8-bit character
flag = boolean (0 or -1)
n = signed 16-bit
u = unsigned 16-bit
d = signed 32-bit
ud = unsigned 32-bit
+n = unsigned 15-bit
x = any cell value
i*x j*x = any number of cell values
a-addr = aligned address
c-addr = character address
p-addr = I/O port address
sys = system-specific

Refer to ANS Forth document for more details.

Low-Level Words (Written in CODE)

ANS Forth Core Words

These are required words whose definitions are specified by the ANS Forth document.

Word	Stack Effect	Description
`!`	`x a-addr --`	Store cell in memory
`+`	`n1/u1 n2/u2 -- n3/u3`	Add n1+n2
`+!`	`n/u a-addr --`	Add cell to memory
`-`	`n1/u1 n2/u2 -- n3/u3`	Subtract n1-n2
`<`	`n1 n2 -- flag`	Test n1<n2, signed
`=`	`x1 x2 -- flag`	Test x1=x2
`>`	`n1 n2 -- flag`	Test n1>n2, signed
`>R`	`x -- R: -- x`	Push to return stack
`?DUP`	`x -- 0 \| x x`	DUP if nonzero
`@`	`a-addr -- x`	Fetch cell from memory
`0<`	`n -- flag`	True if TOS negative
`0=`	`n/u -- flag`	Return true if TOS=0
`1+`	`n1/u1 -- n2/u2`	Add 1 to TOS
`1-`	`n1/u1 -- n2/u2`	Subtract 1 from TOS
`2*`	`x1 -- x2`	Arithmetic left shift
`2/`	`x1 -- x2`	Arithmetic right shift
`AND`	`x1 x2 -- x3`	Logical AND
`CONSTANT`	`n --`	Define a Forth constant
`C!`	`c c-addr --`	Store char in memory
`C@`	`c-addr -- c`	Fetch char from memory
`DROP`	`x --`	Drop top of stack
`DUP`	`x -- x x`	Duplicate top of stack
`EMIT`	`c --`	Output character to console
`EXECUTE`	`ix xt -- jx`	Execute Forth word 'xt'
`EXIT`	`--`	Exit a colon definition
`FILL`	`c-addr u c --`	Fill memory with char
`I`	`-- n R: sys1 sys2 -- sys1 sys2`	Get the innermost loop index
`INVERT`	`x1 -- x2`	Bitwise inversion
`J`	`-- n R: 4sys -- 4sys`	Get the second loop index
`KEY`	`-- c`	Get character from keyboard
`LSHIFT`	`x1 u -- x2`	Logical L shift u places
`NEGATE`	`x1 -- x2`	Two's complement
`OR`	`x1 x2 -- x3`	Logical OR
`OVER`	`x1 x2 -- x1 x2 x1`	Per stack diagram
`ROT`	`x1 x2 x3 -- x2 x3 x1`	Per stack diagram
`RSHIFT`	`x1 u -- x2`	Logical R shift u places
`R>`	`-- x R: x --`	Pop from return stack
`R@`	`-- x R: x -- x`	Fetch from return stack
`SWAP`	`x1 x2 -- x2 x1`	Swap top two items
`UM*`	`u1 u2 -- ud`	Unsigned 16x16->32 mult.
`UM/MOD`	`ud u1 -- u2 u3`	Unsigned 32/16->16 div.
`UNLOOP`	`-- R: sys1 sys2 --`	Drop loop parameters
`U<`	`u1 u2 -- flag`	Test u1<n2, unsigned
`VARIABLE`	`--`	Define a Forth variable
`XOR`	`x1 x2 -- x3`	Logical XOR

ANS Forth Extensions

Optional words specified by the ANS Forth document.

Word	Stack Effect	Description
`<>`	`x1 x2 -- flag`	Test not equal
`BYE`	`i*x --`	Return to CP/M
`CMOVE`	`c-addr1 c-addr2 u --`	Move from bottom
`CMOVE>`	`c-addr1 c-addr2 u --`	Move from top
`KEY?`	`-- flag`	Return true if char waiting
`M+`	`d1 n -- d2`	Add single to double
`NIP`	`x1 x2 -- x2`	Per stack diagram
`TUCK`	`x1 x2 -- x2 x1 x2`	Per stack diagram
`U>`	`u1 u2 -- flag`	Test u1>u2, unsigned

Private Extensions

Words unique to CamelForth.

Word	Stack Effect	Description
`(DO)`	`n1\|u1 n2\|u2 -- R: -- sys1 sys2`	Run-time code for DO
`(LOOP)`	`R: sys1 sys2 -- \| sys1 sys2`	Run-time code for LOOP
`(+LOOP)`	`n -- R: sys1 sys2 -- \| sys1 sys2`	Run-time code for +LOOP
`><`	`x1 -- x2`	Swap bytes
`?BRANCH`	`x --`	Branch if TOS zero
`BDOS`	`DE C -- A`	Call CP/M BDOS
`BRANCH`	`--`	Branch always
`LIT`	`-- x`	Fetch inline literal to stack
`RP!`	`a-addr --`	Set return stack pointer
`RP@`	`-- a-addr`	Get return stack pointer
`SCAN`	`c-addr1 u1 c -- c-addr2 u2`	Find matching char
`SKIP`	`c-addr1 u1 c -- c-addr2 u2`	Skip matching chars
`SP!`	`a-addr --`	Set data stack pointer
`SP@`	`-- a-addr`	Get data stack pointer
`S=`	`c-addr1 c-addr2 u -- n`	String compare (n<0: s1<s2, n=0: s1=s2, n>0: s1>s2)
`USER`	`n --`	Define user variable 'n'

High-Level Words

ANS Forth Core Words

These are required words whose definitions are specified by the ANS Forth document.

Word	Stack Effect	Description
`#`	`ud1 -- ud2`	Convert 1 digit of output
`#S`	`ud1 -- ud2`	Convert remaining digits
`#>`	`ud1 -- c-addr u`	End conversion, get string
`'`	`-- xt`	Find word in dictionary
`(`	`--`	Skip input until )
`*`	`n1 n2 -- n3`	Signed multiply
`*/`	`n1 n2 n3 -- n4`	n1*n2/n3
`*/MOD`	`n1 n2 n3 -- n4 n5`	n1*n2/n3, rem & quot
`+LOOP`	`adrs -- L: 0 a1 a2 .. aN --`
`,`	`x --`	Append cell to dict
`/`	`n1 n2 -- n3`	Signed divide
`/MOD`	`n1 n2 -- n3 n4`	Signed divide, rem & quot
`:`	`--`	Begin a colon definition
`;`		End a colon definition
`<#`	`--`	Begin numeric conversion
`>BODY`	`xt -- a-addr`	Address of param field
`>IN`	`-- a-addr`	Holds offset into TIB
`>NUMBER`	`ud adr u -- ud' adr' u'`	Convert string to number
`2DROP`	`x1 x2 --`	Drop 2 cells
`2DUP`	`x1 x2 -- x1 x2 x1 x2`	Dup top 2 cells
`2OVER`	`x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2`	Per diagram
`2SWAP`	`x1 x2 x3 x4 -- x3 x4 x1 x2`	Per diagram
`2!`	`x1 x2 a-addr --`	Store 2 cells
`2@`	`a-addr -- x1 x2`	Fetch 2 cells
`ABORT`	`ix -- R: jx --`	Clear stack & QUIT
`ABORT"`	`ix 0 -- ix R: jx -- jx`	Print msg & abort if x1<>0
`ABS`	`n1 -- +n2`	Absolute value
`ACCEPT`	`c-addr +n -- +n'`	Get line from terminal
`ALIGN`	`--`	Align HERE
`ALIGNED`	`addr -- a-addr`	Align given addr
`ALLOT`	`n --`	Allocate n bytes in dict
`BASE`	`-- a-addr`	Holds conversion radix
`BEGIN`	`-- adrs`	Target for backward branch
`BL`	`-- char`	An ASCII space
`C,`	`char --`	Append char to dict
`CELLS`	`n1 -- n2`	Cells->adrs units
`CELL+`	`a-addr1 -- a-addr2`	Add cell size to adrs
`CHAR`	`-- char`	Parse ASCII character
`CHARS`	`n1 -- n2`	Chars->adrs units
`CHAR+`	`c-addr1 -- c-addr2`	Add char size to adrs
`COUNT`	`c-addr1 -- c-addr2 u`	Counted->adr/len
`CR`	`--`	Output newline
`CREATE`	`--`	Create an empty definition
`DECIMAL`	`--`	Set number base to decimal
`DEPTH`	`-- +n`	Number of items on stack
`DO`	`-- adrs L: -- 0`	Start of DO..LOOP
`DOES>`	`--`	Change action of latest def'n
`ELSE`	`adrs1 -- adrs2`	Branch for IF..ELSE
`ENVIRONMENT?`	`c-addr u -- false`	System query
`EVALUATE`	`ix c-addr u -- jx`	Interpret string
`FIND`	`c-addr -- c-addr 0`	If name not found
	`xt 1`	If immediate
	`xt -1`	If "normal"
`FM/MOD`	`d1 n1 -- n2 n3`	Floored signed division
`HERE`	`-- addr`	Returns dictionary pointer
`HOLD`	`char --`	Add char to output string
`IF`	`-- adrs`	Conditional forward branch
`IMMEDIATE`	`--`	Make last def'n immediate
`LEAVE`	`-- L: -- adrs`	Exit DO..LOOP
`LITERAL`	`x --`	Append numeric literal to dict
`LOOP`	`adrs -- L: 0 a1 a2 .. aN --`
`MAX`	`n1 n2 -- n3`	Signed maximum
`MIN`	`n1 n2 -- n3`	Signed minimum
`MOD`	`n1 n2 -- n3`	Signed remainder
`MOVE`	`addr1 addr2 u --`	Smart move
`M*`	`n1 n2 -- d`	Signed 16*16->32 multiply
`POSTPONE`	`--`	Postpone compile action of word
`QUIT`	`-- R: i*x --`	Interpret from keyboard
`RECURSE`	`--`	Recurse current definition
`REPEAT`	`adrs1 adrs2 --`	Resolve WHILE loop
`SIGN`	`n --`	Add minus sign if n<0
`SM/REM`	`d1 n1 -- n2 n3`	Symmetric signed division
`SOURCE`	`-- adr n`	Current input buffer
`SPACE`	`--`	Output a space
`SPACES`	`n --`	Output n spaces
`STATE`	`-- a-addr`	Holds compiler state
`S"`	`--`	Compile in-line string
`."`	`--`	Compile string to print
`S>D`	`n -- d`	Single -> double precision
`THEN`	`adrs --`	Resolve forward branch
`TYPE`	`c-addr +n --`	Type line to terminal
`UNTIL`	`adrs --`	Conditional backward branch
`U.`	`u --`	Display u unsigned
`.`	`n --`	Display n signed
`WHILE`	`-- adrs`	Branch for WHILE loop
`WORD`	`char -- c-addr n`	Parse word delim by char
`[`	`--`	Enter interpretive state
`[CHAR]`	`--`	Compile character literal
`[']`	`--`	Find word & compile as literal
`]`	`--`	Enter compiling state

ANS Forth Extensions

Optional words specified by the ANS Forth document.

Word	Stack Effect	Description
`.S`	`--`	Print stack contents
`/STRING`	`a u n -- a+n u-n`	Trim string
`AGAIN`	`adrs --`	Uncond'l backward branch
`COMPILE,`	`xt --`	Append execution token
`DABS`	`d1 -- +d2`	Absolute value, dbl.prec.
`DNEGATE`	`d1 -- d2`	Negate, double precision
`HEX`	`--`	Set number base to hex
`PAD`	`-- a-addr`	User PAD buffer
`TIB`	`-- a-addr`	Terminal Input Buffer
`WITHIN`	`n1\|u1 n2\|u2 n3\|u3 -- f`	Test n2<=n1<n3?
`WORDS`	`--`	List all words in dict.

Private Extensions

Words unique to CamelForth.

Word	Stack Effect	Description
`!CF`	`adrs cfa --`	Set code action of a word
`!COLON`	`--`	Change code field to docolon
`!DEST`	`dest adrs --`	Change a branch dest'n
`#INIT`	`-- n`	#bytes of user area init data
`'SOURCE`	`-- a-addr`	Two cells: len, adrs
`(DOES>)`	`--`	Run-time action of DOES>
`(S")`	`-- c-addr u`	Run-time code for S"
`,BRANCH`	`xt --`	Append a branch instruction
`,CF`	`adrs --`	Append a code field
`,DEST`	`dest --`	Append a branch address
`,EXIT`	`--`	Append hi-level EXIT action
`>COUNTED`	`src n dst --`	Copy to counted str
`>DIGIT`	`n -- c`	Convert to 0..9A..Z
`>L`	`x -- L: -- x`	Move to Leave stack
`?ABORT`	`f c-addr u --`	Abort & print msg
`?DNEGATE`	`d1 n -- d2`	Negate d1 if n negative
`?NEGATE`	`n1 n2 -- n3`	Negate n1 if n2 negative
`?NUMBER`	`c-addr -- n -1`	Convert string->number
	`-- c-addr 0`	If convert error
`?SIGN`	`adr n -- adr' n' f`	Get optional sign
`CELL`	`-- n`	Size of one cell
`COLD`	`--`	Cold start Forth system
`COMPILE`	`--`	Append inline execution token
`DIGIT?`	`c -- n -1`	If c is a valid digit
	`-- x 0`	Otherwise
`DP`	`-- a-addr`	Holds dictionary ptr
`ENDLOOP`	`adrs xt -- L: 0 a1 a2 .. aN --`
`HIDE`	`--`	"hide" latest definition
`HP`	`-- a-addr`	HOLD pointer
`IMMED?`	`nfa -- f`	Fetch immediate flag
`INTERPRET`	`ix c-addr u -- jx`	Interpret given buffer
`L0`	`-- a-addr`	Bottom of Leave stack
`LATEST`	`-- a-addr`	Last word in dictionary
`LP`	`-- a-addr`	Leave-stack pointer
`L>`	`-- x L: x --`	Move from Leave stack
`NFA>CFA`	`nfa -- cfa`	Name adr -> code field
`NFA>LFA`	`nfa -- lfa`	Name adr -> link field
`R0`	`-- a-addr`	End of return stack
`REVEAL`	`--`	"reveal" latest definition
`S0`	`-- a-addr`	End of parameter stack
`TIBSIZE`	`-- n`	Size of TIB
`U0`	`-- a-addr`	Current user area adrs
`UD*`	`ud1 d2 -- ud3`	32*16->32 multiply
`UD/MOD`	`ud1 u2 -- u3 ud4`	32/16->32 divide
`UINIT`	`-- addr`	Initial values for user area
`UMAX`	`u1 u2 -- u`	Unsigned maximum
`UMIN`	`u1 u2 -- u`	Unsigned minimum

Forth Programming Examples

Here is the quintessential introduction to Forth, originating from the era of early 8-bit personal computers.

https://www.forth.com/starting-forth/

1. Basic Stack Manipulation

\ Example of basic stack operations
5 3 2    \ Put three numbers on the stack
.S       \ Print stack contents -- output: 5 3 2
DUP      \ Duplicate top number
.S       \ Stack now: 5 3 2 2
SWAP     \ Swap top two numbers
.S       \ Stack now: 5 3 2 2
DROP     \ Remove top number
.        \ Print top number
CR       \ Carriage return (newline)

2. Simple Calculator

\ Definition for squaring a number
: SQUARE ( n -- n^2 )
    DUP *
;

\ Definition for cube
: CUBE ( n -- n^3 )
    DUP SQUARE *
;

\ Example usage
5 SQUARE .  \ Outputs: 25
3 CUBE .    \ Outputs: 27

\ Basic arithmetic calculator
: CALCULATE ( n1 n2 -- )
    2DUP + ." Sum: " . CR
    2DUP - ." Difference: " . CR
    2DUP * ." Product: " . CR
    SWAP DUP 0= IF 
        DROP DROP ." Division by zero! " CR
    ELSE
        / ." Quotient: " . CR
    THEN
;

10 5 CALCULATE

3. String Handling

\ Print a string
: GREET ( -- )
    ." Hello, Forth Programmer!" CR
;

\ Count characters in a string
: COUNT-CHARS ( addr u -- n )
    0 DO
        1+
    LOOP
;

\ Example of string comparison
: SAME-STRING? ( addr1 u1 addr2 u2 -- flag )
    ROT SWAP                \ Reorder parameters
    S=                      \ Compare strings
    0=                      \ Convert to boolean
;

4. Simple Loop Examples

\ Print numbers from 1 to n
: COUNT-TO ( n -- )
    1+ 1 DO
        I .
        SPACE
    LOOP
    CR
;

\ Print a multiplication table
: TIMES-TABLE ( n -- )
    CR
    ." Multiplication table for " DUP . CR
    11 1 DO
        DUP I * .
        SPACE
    LOOP
    DROP
    CR
;

\ Example usage:
5 COUNT-TO      \ Prints: 1 2 3 4 5
7 TIMES-TABLE   \ Prints multiplication table for 7

5. Memory Operations

\ Create a variable
VARIABLE COUNT
0 COUNT !      \ Initialize to 0

\ Increment counter
: INC-COUNT ( -- )
    1 COUNT +!
;

\ Reset counter
: RESET-COUNT ( -- )
    0 COUNT !
;

\ Show counter
: SHOW-COUNT ( -- )
    ." Counter: "
    COUNT @ .
    CR
;

\ Example usage:
SHOW-COUNT     \ Shows: Counter: 0
INC-COUNT
INC-COUNT
SHOW-COUNT     \ Shows: Counter: 2
RESET-COUNT
SHOW-COUNT     \ Shows: Counter: 0

6. Simple Data Structure (Stack)

\ Implementation of a small stack (max 10 items)
CREATE STACK 10 CELLS ALLOT
VARIABLE STACK-PTR
0 STACK-PTR !

: STACK-PUSH ( n -- )
    STACK-PTR @ 9 > IF
        ." Stack overflow! " DROP
    ELSE
        STACK-PTR @ CELLS STACK + !
        1 STACK-PTR +!
    THEN
;

: STACK-POP ( -- n )
    STACK-PTR @ 0= IF
        ." Stack underflow! " 0
    ELSE
        -1 STACK-PTR +!
        STACK-PTR @ CELLS STACK + @
    THEN
;

\ Example usage:
5 STACK-PUSH
10 STACK-PUSH
STACK-POP .    \ Outputs: 10
STACK-POP .    \ Outputs: 5

7. Conditional Examples

\ Check if a number is positive, negative, or zero
: CHECK-NUMBER ( n -- )
    DUP 0= IF
        ." Number is zero" CR DROP
    ELSE
        DUP 0< IF
            ." Number is negative" CR DROP
        ELSE
            ." Number is positive" CR DROP
        THEN
    THEN
;

\ Example usage:
5 CHECK-NUMBER    \ Outputs: Number is positive
-3 CHECK-NUMBER   \ Outputs: Number is negative
0 CHECK-NUMBER    \ Outputs: Number is zero

These examples demonstrate basic Forth programming concepts including:

Stack manipulation
Arithmetic operations
String handling
Loops and iteration
Memory operations
Simple data structures
Conditional statements

Each example includes comments explaining the operations and expected output. Remember that Forth is a stack-based language, so understanding stack manipulation is crucial for writing effective programs.

Name		Name	Last commit message	Last commit date
Latest commit History 43 Commits
CPM-sd-image		CPM-sd-image
Components		Components
ROMS		ROMS
Z80 CPM and bootloader (basmon)		Z80 CPM and bootloader (basmon)
releases		releases
rtl		rtl
sys		sys
.gitignore		.gitignore
Microcomputer6502Basic.vhd		Microcomputer6502Basic.vhd
Microcomputer6809Basic.vhd		Microcomputer6809Basic.vhd
MicrocomputerZ80Basic.vhd		MicrocomputerZ80Basic.vhd
MicrocomputerZ80CPM.vhd		MicrocomputerZ80CPM.vhd
MultiComp-lite.qsf		MultiComp-lite.qsf
MultiComp-lite.srf		MultiComp-lite.srf
MultiComp.qpf		MultiComp.qpf
MultiComp.qsf		MultiComp.qsf
MultiComp.srf		MultiComp.srf
MultiComp.sv		MultiComp.sv
README.md		README.md
build_id.v		build_id.v
c5_pin_model_dump.txt		c5_pin_model_dump.txt
clean.bat		clean.bat
jtag.cdf		jtag.cdf
pll.xml		pll.xml

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MiSTer MultiComp

Using the MiSTer Serial Terminal/Console

Connection Methods

Setting Up the Connection

For UART/Serial with PuTTY

USB to serial cable connection

User Port - extra USB 3.1A style connector on MiSTer

FT232 USB to serial cable

For SSH with PuTTY

Linux command line to establish the connection to the core

Additional Information

The MiSTer OSD allows the access to five machines

Z80 CP/M

Formatting the SD Card and Installing CP/M

Formatting the Drive

Installing CP/M

Boot CP/M from image file

Z80 Basic

6502 Basic - No SD card support (No CSAVE/CLOAD)

6809 Basic - No SD card support(No CSAVE/CLOAD)

6809 Camel Forth

MultiComp OSD Configuration

Menu Structure

System Control

CPU and ROM Configuration

Communication Settings

Additional Information

Troubleshooting

Serial Communication Issues

Storage Issues

System Stability

Known Limitations

License

Original Author

URL

MiSTer MultiComp BASIC Keywords Reference

Keywords by Category

Mathematical Functions

String Functions

Program Control

Data and Variables

System and Memory

Program Editing

Z80 BASIC Specific Extensions (v4.7b)

Operators

BASIC Programming Examples

Number Guessing Game

String Manipulation

Math Functions Calculator

Array Operations

Simple Data Management

Custom Function Definition

Forth Language Glossary

Guide to Stack Diagrams

Low-Level Words (Written in CODE)

ANS Forth Core Words

ANS Forth Extensions

Private Extensions

High-Level Words

ANS Forth Core Words

ANS Forth Extensions

Private Extensions

Forth Programming Examples

1. Basic Stack Manipulation

2. Simple Calculator

3. String Handling

4. Simple Loop Examples

5. Memory Operations

6. Simple Data Structure (Stack)

7. Conditional Examples

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