A lightweight BASIC implementation for embedded systems.

• Tokenized execution - Programs are compiled to bytecode for efficient execution
• 26 variables (A-Z)
• Control flow - IF/THEN/ELSE, GOTO
• I/O - PRINT, INPUT
• Hardware access - PEEK/POKE for access to hardware
• Arithmetic - Addition, subtraction, multiplication, division
• Comparisons - <, >, <=, >=, <>, ==

• Linux
• Werkzeug
• Blaustahl
• Zwölf LS10A

$ make
$ ./basic

$ cd targets/ls10
$ git clone https://github.com/cnlohr/ch32fun
$ make

You will need to have pico-sdk installed in your path. The following commands will produce a UF2 file that you can use to update the firmware on the device.

$ cd targets/werkzeug
$ mkdir build
$ cd build
$ cmake -DPICO_BOARD=machdyne_werkzeug ..
$ make

$ cd targets/blaustahl
$ mkdir build
$ cd build
$ cmake ..
$ make

Programs consist of numbered lines:

10 PRINT "HELLO"
20 LET A = 5
30 PRINT A

Assign a value to a variable:

LET A = 10
LET B = A + 5

Output text or expressions:

PRINT "HELLO"
PRINT 42
PRINT A + B

Read a value from the user:

INPUT A
INPUT "ENTER YOUR AGE: ", A

Conditional execution:

10 INPUT A
20 IF A > 10 THEN PRINT "BIG"
30 IF A < 5 THEN PRINT "SMALL" ELSE PRINT "MEDIUM"

Jump to a line number:

10 LET A = 0
20 PRINT A
30 LET A = A + 1
40 IF A < 10 THEN GOTO 20
50 PRINT "DONE"

Turn an LED on or off on LS10:

10 POKE 16, 128
20 INPUT "LED 0 or 1:", L
30 IF L == 1 THEN POKE(17, 128) ELSE POKE(17, 0)

Blink LEDs on Werkzeug:

10 POKE(18,255)
20 LET A = 0
30 IF A == 0 THEN LET A = 255 ELSE LET A = 0
40 POKE(23,A)
50 SLEEP 1
60 GOTO 30

Sleep for a number of seconds:

10 PRINT "SLEEPING"
20 SLEEP 3
30 PRINT "AWAKE"

Arithmetic: +, -, *, /

Comparison: <, >, <=, >=, <> (not equal), == (equal)

Parentheses: ( and ) for grouping

Execute the stored program:

> RUN

Display the stored program:

> LIST
10 PRINT "HELLO"
20 INPUT A
30 PRINT A

Type just the line number:

> 20

> SAVE HELLO.BAS

> LOAD HELLO.BAS

10 PRINT "HELLO WORLD"

10 LET A = 1
20 PRINT A
30 LET A = A + 1
40 IF A <= 10 THEN GOTO 20
50 PRINT "DONE"

10 PRINT "WHAT IS YOUR BIRTH YEAR?"
20 INPUT Y
30 LET A = 2025 - Y
40 PRINT "YOU ARE "
50 PRINT A
60 PRINT " YEARS OLD"

• Program storage: 1024 bytes
• Variables: 26 signed 16-bit integers (A-Z)
• PEEK/POKE memory: 256 bytes

Programs are tokenized into bytecode:

• Single-byte tokens: Keywords, operators
• Multi-byte tokens:
  • Numbers: TOK_NUM + 2 bytes (little-endian)
  • Strings: TOK_STR + length + data
  • Variables: TOK_VAR + index (0-25)

Each program line:

[line# low] [line# high] [length] [tokens...] [TOK_EOL]

• Maximum 1024 bytes total program storage
• 26 variables (A-Z only)
• 16-bit signed integers only (-32768 to 32767)
• No floating point
• No arrays
• No string variables (only string literals in PRINT)
• No FOR/NEXT loops (use GOTO)
• No subroutines/GOSUB

To the extent that there is LLM-generated code in this repo, it should be space indented. Any space indented code should be carefully audited and then converted to tabs (eventually).

The contents of this repo are released under the Lone Dynamics Open License.