General Video Assembler.
By General Video (Steve Walter and Dave Ibach).
Arcadian 4, no. 12 (Oct. 07, 1982): 123. (First Advertisement)
Arcadian 5, no. 4 (Feb. 18, 1983): 57. (Review)
Requires: "AstroBASIC" and a minimum of 4K add-On RAM expansion.
This machine language assembler cost $35. Here is an overview of it from an ad in the October 1982 Arcadian:
Speak to your Astrocade in its native language!
The General Video Assembler software can be downloaded here:
- Uses standard Z80 mnemonics
- Has complete editing facilities
- Prints extensive error messages
- Provides symbolic access to BASIC's variables
- Create object programs of unlimited size
- Requires Astrovision BASIC with taping facility and 4K (minimum) of add-on memory switchable between 6K and 2K address ranges (like Blue Ram)
This 16-page manual is quite extensive. Here is the complete first page from the manual. It gives the user an indication of what the program can do on the Astrocade.
- General Video Assembler - The General Video Assembler is made-up of four programs: Collector, Pass I, Pass II and Text Editor. Also included are two sample programs: Flying Witch, and Logo.
Provided in this manual is a comprehensive description of the General Video Assembler for the Z80-based Astrocade. The General Video Assembler includes an editor for preparation of the source program, Pass I and Pass II which translate Z8O source statements into hexadecimal, and the Collector for joining together multiple segments.
An assembler is different from [an interpreter]. Your Astrocade BASIC is [an interpreter]. It can execute a BASIC program directly by a RUN command, translating each BASIC statement before executing it. Consequently a BASIC [interpreter] is very convenient, but also very slow in execution since every statement must be translated before execution.
With an assembler, the source program cannot simply be RUN. It must first be assembled. This is a one-time process, converting source statements to hexadecimal, and is completely finished by the time the object program is CALLed. A change in the source program requires a new assembly. Since no translation goes on during execution, the speed is greatly increased.
It is not the purpose of this manual to teach Z8O machine coding. If you have experience with other assembler languages and understand hexadecimal, and need only a familiarity with the processor architecture and instructions, then you can get by with the Z80 Instruction Handbook by Nat Wadsworth (SCELBI Publications, 1978, about $6). Otherwise, get a more comprehensive textbook, like Programming the Z80 by Rodney Zaks (Sybex, 1980, about $12).
An Astrocade game computer, Astrocade BASIC with taping facilities and add-on memory is required. The add-on memory must be at least 4K (hex) in size and it must be switch able from the 2K (hex) to the 6K (hex) address ranges (like the Blue RAM or Viper).
Since there is no floppy disk capability, all intermediate files must be recorded on tape. Thus tape handling can be excessive at times, in spite of operational streamlining. This is true in particular of multi-segment programs. To facilitate this, the user is strongly urged to install an I/O switch for switching between input and output taping. Steve Walters explained how to do this in Arcadian 4, no. 2 (Dec. 07, 1981): 16.
General Video Assembler (Sample Programs).|
By Dave Ibach.
Michael White created these handwritten Z80 assembly language listings of the two sample demonstration programs included on the General Video Assembler tape: Flying Witch and Logo.