tylko ze na commodorka

The first prototype

The first prototype was done relatively fast and indicated that there still were a number of bugs in the core. A funny side effect was that this core supported a number of illegal opcodes. It was said that illegal opcodes are a by-product of the original opcodes and this incident proved it was true. A quick review showed that not all known original opcodes were present but this is not surprising if you look at how the 6502 and the 65GZ02 are developed.

The next step was to determine what the new processor would be required to do. Ideas had developed in a way that one could barely speak of a processor any longer. The first idea was to make it a 32 bit CPU: The 65GZ032. For your referrence: The Motorola 68040 and Intel 80486 are 32 bit CPUs too. But such a CPU only comes into its own if it has enough memory available. The C64 can not support this memory so a mechanism has to be integrated to support SDRAM modules. Considering today's standards the C64 is limited in its capabilities to support external devices like floppy drives, hard drives and CD-ROM drives. An improvement of the video output also should do no harm. After much thinking and considering and a number of discussions the decision was made to add PCI and 16 bit ISA bus to the processor. This enables the user to equip his 20 year old C64 in a very simple way with current technology stuff.

Jeri Ellsworth

The 65GZ032 was intended primarily for the C64 to assist the 6510 processor. Gideon is not the only person eager to enhance the C64, though. The American Jeri Ellsworth began development of a successor of the video chip of the C64 two years ago. This chip, among other things, should make it possible to get much better resolutions on a VGA monitor. But during time the project grew and after all resulted in the CommodoreOne (also C=1), some kind of C64 clone only much better. This project also has been put into reality as FPGA with one exception: The processor. Jeri did not have enough time and knowledge of the 6502 processor to develop a core for this too and used the 65816 core instead. In the Commodore world, almost everybody knows almost everybody else and it didn't take long and Gideon and Jeri were up to date with each other's development. From this it followed that the 65GZ032 developed by Gideon could be connected to the expansion port of the C=1. This way, Jeri solved her problem with her processor.

Commodore built different computers and unfortunately, they use different processors. Fortunately, they are all based on the 6502. The different pieces are so small that Gideon decided to make the print in a way that the 65GZ032 can also emulate the 8502 (C128), 8501 (C16, Plus4), a 6502 (VIC-20) and others. The latest developmet has another advantage: Making it more versatile allows for a bigger market (6502: Atari, Apple!!!). The advantage is that with the production of larger numbers of PCBs the costs are reduced and thus more people are attracted and also writing software becomes more attractive.

In summary, the first prototype of the 65GZ032 should run in the C=1. Also, there is a first idea for a 65GZ032 assembler which in turn enables other programmers to port existing 6502 code to 65GZ032 code. We will keep you updated on the latest developments.