About the Emulator
About version 0.6a

The 0.6a version fixes many bugs in the display routines and has better presentation. It has snapshot support and now should support multicolour mode properly but this has not been fully tested.Command ket combinations now work and joystick support has been added. Note that this is still an alpha version and while I have not heard of any bugs other than those listed below, it has not been tested to find how stable it actually is.

A little info to make up for the lack of instructions.

The emulator as far as I know runs all VIC 20 BASIC programs excluding some that access I/O ports directly. Still not emulated are sound,serial ports, disk drives, printers tapes and most of the VIA chips (Most of these are driven by the VIA). Support for many of these will come in future versions as will many bugfixes and perfomance enhancements. Most VIC 20 keys are mapped to the equivelent Macintosh keys but the RESTORE key is not yet implemented. 'esc' functions as the RUN/STOP key. The C= and SHIFT combination now works properly. Option is the C= key. To load files you find on the internet you will need to use the import command....they can't be loaded as snapshots yet. The joystick is now emulated and uses the numeric keypad. The key layout is....

8(up)

4(left) 6(right)

2(down)

....and enter on the numeric keypad is the fire button. I know it's a little awkward but I wanted to make sure I didn't alter the effects of any other keys.I'll try to make it better in the next version.

Known Bugs in 0.6a

  • typing a non-numerical value into the address & length fields of the disassembler or memory dump routines will crash the machine.
  • The joystick menu has no effect...

Coming in the next version. (current status in green)

  • Correct screen size and handling. (Partially working but not compatible enough yet)
  • The faster 6502 engine working again and completed. (Complete but still buggy)
  • Support for a new cross platform snapshot format. (still to be coded and finalised)
  • A moveable window...(fully working now)
  • More correct timing. (Some improvements working)
  • A faster graphics engine... (Partially done. Speed is quadrupled but it is very buggy)

Unfortunately the new graphics engine will take memory requirements up by 1Mb. Also full screen mode is impossible as whatever resolution is used, the VIC's strange resoultion doesn't fill the screen.

When is it Coming?

Some of these features may be changed before the next version is released. The new file format for example is not entirely ready to be implemented yet whereas a new more powerful and reliable debugger may be added. Also if I work out a better way of doing something then I may hold back that feature to the next release. I aim to have the new version out before July at the latest. It will take this long because I don't have very much time to code while I'm at University and the features I want to add make for major modifications to the code. The new 6502 engine alone accounts for over half the code in the current version but this is changing with the new graphics routines that are being added.

I plan to keep adding features to the emulator until it gets to the point that it supports most if not all of the VIC-20 features. Until then it is going to remain as an alpha or beta release. Once I get to the point that I'm satisfied with the features then I will stress-test it fully to eliminate any existing bugs and release it properly with full documentation and some software.

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(c)1997 Matthew Browne