6basic

Commodore 64 BASIC 2.0 cross-compiler. Write BASIC in a text editor with labels, macros and named PETSCII codes, and get a normal .prg. Also lists and detokenizes existing programs, and has a turbo mode that replaces GOTO and GOSUB line searches with direct pointers.

Linux x64	6basic-2026.11.06-linux-x64.tar.gz	28 MB
Windows x64	6basic-2026.11.06-win-x64.zip	28 MB

Built 2026-11-06 from 6ea7bcf. Self-contained: no .NET install needed. SHA256SUMS

Unpack and put 6basic on your PATH. The Windows binary is unsigned, so SmartScreen may warn. {asm} blocks also need 6asm on your PATH.

Full reference: every option and source enhancement, and what isn't implemented yet.

Example

Source (bars.bas):

' bars.bas: labels instead of line numbers, macros for the colours
{#BORDER|53280}
{#PAPER|53281}

10 POKE {#BORDER},0:POKE {#PAPER},0
20 PRINT "{clear}{white}6basic sample{down:1}"
30 FOR I=1 TO 6:GOSUB {:BAR}:NEXT I
40 PRINT "{down}{yellow}tokenized from plain text."
50 PRINT "{light blue}labels resolve at compile time."
60 END

{:BAR}
100 RESTORE:FOR J=1 TO I:READ C$:NEXT J
110 PRINT C$;"{reverse on}                              {reverse off}"
120 RETURN
130 DATA "{red}","{orange}","{yellow}","{green}","{cyan}","{purple}"

$ 6basic bars.bas
Wrote bars.prg
$ 6basic listbasic bars.prg
10 POKE 53280,0:POKE 53281,0
20 PRINT "{clear}{white}6basic sample{down}"
30 FOR I=1 TO 6:GOSUB 100:NEXT I
40 PRINT "{down}{yellow}tokenized from plain text."
50 PRINT "{light blue}labels resolve at compile time."
60 END
100 RESTORE:FOR J=1 TO I:READ C$:NEXT J
110 PRINT C$;"{reverse on}                              {reverse off}"
120 RETURN
130 DATA "{red}","{orange}","{yellow}","{green}","{cyan}","{purple}"
$ 6basic bas2prg -f -turbo-data bars.bas bars-turbo.prg
Wrote bars-turbo.prg
$ wc -c bars*.prg
727 bars-turbo.prg
266 bars.prg
993 total

bars.prg in VICE. Text inside quotes is case-inverted on the way in, so write lower case to see upper case on the default charset.

Commands


`6basic game.bas`	source to `game.prg`
`6basic bas2prg game.bas out.prg`	the same, explicit
`6basic prg2bas game.prg game.bas`	detokenize to text
`6basic listbasic game.prg`	list to the terminal
`6basic dumpbasic game.prg`	hex dump
`6basic game.bas -prg:build/game -hex`	several outputs in one run

Source language


`{:LOOP}`	a label; `GOTO {:LOOP}` resolves to a line number at compile time
`{#BORDER\\|53280}`	replacement macro, used as `{#BORDER}`
`{clear}` `{red}` `{f1}` `{down:5}`	named PETSCII codes, with repeat
`{$0B}`	any byte
`' comment`	stripped before tokenizing
`{ifdef:NAME}` `{usedef:NAME}`	conditional compilation, with `-def:` on the command line
`{asm}` ...	inline assembly through 6asm

Errors give the file and line, and nothing is written when compilation fails:

$ printf '10 GOTO {:NOPE}\n' > bad.bas
$ 6basic bad.bas
error: [bad.bas (1)] Undefined label {:NOPE} in: GOTO {:NOPE}
==== 1 Errors; 0 Warnings ====
Compilation failed (bad.bas): no output written.

Labels can cross files: -labels:lib.lbl exports them and -uselabels:lib.lbl imports them.

Turbo mode

GOTO, GOSUB and THEN targets are compiled to 3-byte pointers instead of ASCII line numbers, so the interpreter does not search for the line. It needs a 122-byte patch at $C000.


`-turbo`	pointer BASIC only; you install the patch
`-turbo-data`	patch included as a self-installing DATA preamble
`-turbo-split`	program plus a separate `.patch.prg`

Turbo programs are not editable on a stock C64. listbasic recognises them and shows line numbers.