64 Forth

64 Forth
Developer	Tom J. Zimmer
Company
Publisher	HES
Release	1983
Licence
Platform	C64, VIC-20
Genre	Programming Language
Operation
Media
Language(s)
Information	Works not on a SX-64!

64FORTH is an implementation of the FORTH programming language. It is a super-set of fig-FORTH. It uses the Commodore file-system and has many functions that access the C64 hardware including sound and graphics. It occupies 16k of cartridge memory from $8000-BFFF and comes with a comprehensive manual. 64FORTH was written by Tom Zimmer and published by HES software in 1983.

Thanks to Tom Zimmer for allowing 64FORTH to be freely distributed. Tom has advised that while 64FORTH is free for anyone to use, he is unable to provide any support or answer queries regarding it.

Thanks also to Jason at This Old Computer for providing a dump of the cartridge.

Included Files

Files in the 64FORTH.zip archive include:

• README.TXT - The basis for this wiki page.
• 64FORTH.TXT - 64FORTH manual
• 64FORTH.ROM - 64FORTH ROM image
• 64FORTH.CRT - 64FORTH in cartridge file format for use with Commodore emulators
• 64FORTH.PRG - A hacked version of 64FORTH that runs in RAM (see patch details below). It has an integrated loader and may be loaded and run like any BASIC program.
• 64FORTH.ASM - A disassembly of the 64FORTH rom in 6502 assembly language.

Notes

1. Those without a Commodore 64 can still run 64FORTH by using an emulator.
2. 64FORTH.PRG and 64FORTH.ASM are "unofficial". If they don't work or have errors, blame not Tom :)
3. 64FORTH.ASM is intended as a basic disassembly only. It uses standard 6502 MOS Technology notation and may be re-assembled using the public domain MS-DOS A65 assembler available here.

Softload Modifications

27/7/85

The following describes an unofficial hack which can be made to the program to allow 64FORTH to be 'soft-loaded' i.e. loaded into memory and run like any other program!

1. SWITCH BASIC OUT

  .: 8027 A9 36 85 01   (REPLACES 'NOP'S )

  LDA #$36
  STA $01

2. PREVENT FORTH FROM SWITCHING IN BASIC

  .: A765 36            (.:A765 37 )

3. PREVENT ERASURE OF $8000 - $83FF

  .: 93F5 D4 86         (REPLACES 'ERASE' WITH '2DROP')

4. PREVENT RESET FROM CORRUPTING $A000

  .: 8021 EA EA EA      (DISABLE RAMTAS ROUTINE $FD50 )

5. COMPUTE NEW CHECKSUM

  .: 9389 F2 82

6. ORIGINAL VALUES

  .: 8021 20 50 FD
  .: 8027 EA EA EA EA
  .: 9389 E4 83
  .: 93F5 45 8E
  .: A765 37

Commands

With the command VLIST can you list all the commands of the 64Forth (see screen shoots).

• 

  64Forth commands 1/4

• 

  64Forth commands 2/4

• 

  64Forth commands 3/4

• 

  64Forth commands 4/4

Links

• Zimmers C64 Programming
• Download 64FORTH.zip
• 64'er: "HES 64Forth"; issue 07/1984