Classic Computer Magazine Archive COMPUTE! ISSUE 40 / SEPTEMBER 1983 / PAGE 183

The VicTree Programming
Module For VIC And 64

Eric Brandon, Programming Assistant

The VicTree, a cartridge for the VIC-20 or the Commodore 64, makes programming more efficient.
    Available for $89.95 from Skyles Electric Works (the originators of the PET "Toolkit"), the VicTree adds 42 commands to BASIC.
    All the commands of PET BASIC 4.0 are supported, which make disk use much easier, especially when trying to program relative files. The BASIC 4.0 commands are not tokenized (converted from what you type into a more memory-efficient form) in the same way as in a "true" BASIC 4.0 machine. Fortunately, the manual contains a program that converts "true" BASIC 4.0 to VicTree format.
    One requirement for using BASIC programs with the VicTree is that you must use a colon between a "THEN" (as in an IF ... THEN statement) and a BASIC 4.0 disk command. The VicTree does not speed up "garbage collection" (the process of removing unwanted or discarded strings from memory) as BASIC 4.0 does, nor will machine language programs written for BASIC 4.0 now run on your VIC or 64.

Added Commands
    Several disk commands not present in BASIC 4.0 have been added, including EXECUTE, which LOADs and RUNs a program all in one step, and CHAIN# which allows an "executive" program to have several BASIC subroutines on disk and load them in only as needed to preserve memory. With this utility, programs can essentially be of unlimited length.
    Another set of commands has been added to assist in program editing. As well as all the standard commands we would expect from any BASIC enhancement package, such as renumbering program lines, finding and changing text, and deleting line ranges, VicTree adds many new and useful commands never before seen in this type of product.
    Among these are the very useful LCOPY and LMOVE commands which let you rearrange the order of the lines in your program. VicTree does not "scroll" through your program like other aids, but supplies a PAGE command that LISTs your program one screen at a time.
    There are also several commands designed to aid in debugging. These are DUMP, which displays the value of all non-array variables; HELP, which shows where an error has occurred; and TRACE, which LISTS out your program lines as they run.
    There are also commands intended for use with any "Centronics" type printer (with no extra hardware needed besides a cable to connect the printer to the parallel user port of your computer). Skyles will supply you with this cable for $29.95, or the VicTree and a cable as a package for $109.95.

Multiple-Computer Communication
Skyles is planning to come out with a device called the Cee-Net which will allow up to 64 VICs or Commodore 64s to communicate with each other and to share disk drives and printers. The VicTree is designed to work with Cee-Net when it arrives and has a command to ATTACH itself to the network.
    On the 64, the VicTree "covers up" memory from 32768 to 40959. This means you have about 30,000 bytes left for your BASIC program. The VicTree also uses up memory from 49152 to 53247, so it cannot be used in conjunction with other software which uses these locations such as the Wedge or Micromon. When used with software that does not require that area of memory, however, it seems to work fine. I have had no trouble using the VicTree with Supermon, and with the PAL assembler.
    On the VIC-20, the VicTree uses locations 24576 to 32767 and 45056 to 49151, leaving 21,000 bytes free if you have enough expansion RAM. If you have an unexpanded VIC, the VicTree will not use up any of your memory.
    The VicTree also allows the machine language programmer to add his own commands to BASIC, with descriptions in the manual of how to do it.
    The manual contains over 100 pages of clearly written in formation about the 42 commands. Each command is given its own page (or more) with examples, explanations, and special notes. Also included is a very complete technical description about the machine language applications of the VicTree. This is one of the most convenient and useful manuals I have ever seen.

Skyles Electric Works
Mountain View, CA 94041
(415) 965-1735