2793c25c9f
* Harmonize drive and disk type hierarchies
Before, the `XXXDrive` and `XXXDisk` type hierarchies were similar,
but not exactly the same. For example, `encoding` and `format` were
missing on some `XXXDisk` types where they existed on the `XXXDrive`
type. This change attempts to bring the hierarchies closer together.
However, the biggest visible consequence is the introduction of the
`FLOPPY_FORMATS` array and its associated `FloppyFormat` type. This
replaces `NIBBLE_FORMATS` in most places. A couple of new type guards
for disk formats and disks have been added as well.
All tests pass, everything compiles with no errors, and both WOZ and
nibble format disks load in the emulator.
* Move disk data to a `disk` field in the drive
Before, disk data was mixed in with state about the drive itself (like
track, motor phase, etc.). This made it hard to know exactly what data
was necessary for different image formats.
Now, the disk data is in a `disk` field whose type depends on the
drive type. This makes responisbility a bit easier.
One oddity, though, is that the `Drive` has metadata _and_ the `Disk`
has metadata. When a disk is in the drive, these should be `===`, but
when there is no disk in the drive, obviously only the drive metadata
is set.
All tests pass, everything compiles, and both WOZ and nibble disks
work in the emulator (both preact and classic).
* Squash the `Drive` type hierarchy
Before, the type of the drive depended on the type of the disk in the
drive. Thus, `NibbleDrive` contained a `NibbleDisk` and a `WozDrive`
contained a `WozDisk`. With the extraction of the disk data to a
single field, this type hierarchy makes no sense. Instead, it
suffices to check the type of the disk.
This change removes the `NibbleDrive` and `WozDrive` types and type
guards, checking the disk type where necessary. This change also
introduces the `NoFloppyDisk` type to represent the lack of a
disk. This allows the drive to have metadata, for one.
All tests pass, everything compiles, and both WOZ and nibble disks
work locally.
* Use more destructuring assignment
Now, more places use constructs like:
```TypeScript
const { metadata, readOnly, track, head, phase, dirty } = drive;
return {
disk: getDiskState(drive.disk),
metadata: {...metadata},
readOnly,
track,
head,
phase,
dirty,
};
```
* Remove the `Disk` object from the `Drive` object
This change splits out the disk objects into a record parallel to the
drive objects. The idea is that the `Drive` structure becomes a
representation of the state of the drive that is separate from the
disk image actually in the drive. This helps in an upcoming
refactoring.
This also changes the default empty disks to be writable. While odd,
the write protect switch should be in the "off" position since there
is no disk pressing on it.
Finally, `insertDisk` now resets the head position to 0 since there is
no way of preserving the head position across disks. (Even in the real
world, the motor-off delay plus spindle spin-down would make it
impossible to know the disk head position with any accuracy.)
apple2js
What is this?
Apple ][js and Apple //jse are Apple ][ and Apple //e emulators written entirely in JavaScript and HTML5.
Things are still a little rough around the edges right now, hopefully I will have more time to clean things up.
First
npm install
To run a development server
npm start
The open either http://localhost:8080/apple2js.html or http://localhost:8080/apple2jse.html
To build a static distribution into dist
npm run build
To add additional disk images, use
./bin/dsk2json -c Category -n Name path/to/image.dsk > json/disks/image.json
then
./bin/index
Updates
2019-03-02
-
Behind the scenes
A lot of not so visible changes behind the scenes. The website now runs directly off of github, and has a more modern toolchain (Goodbye make, Perl and closure compiler, hello Webpack!) to facilitate development.
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Performance
In particular, the screen no longer redraws as quickly as possible.
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Drag and Drop
Disk images can be dragged into the window to load them.
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Contributions
Thanks to Ian Flanigan for additions to improve ChromeBook behavior.
2017-10-08
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Better iOS support
Bluetooth keyboards now work better. Reset is Ctrl-Shift-Delete. iOS now allows loading disks from iCloud and services like Drop Box. Saving locally is still not supported by iOS. I now understand why sound doesn't work, and I'm working on a work-around.
-
Source Maps
Although the source code has always been available, by default I serve up minified Javascript for performance reasons. But now you can poke around more easily.
Updates (2017-08-31)
(It's been a long time since I updated, so this is a rough list)
-
Videx Videoterm Emulation (][js)
PR#3 now does something on the Apple ][!.
-
AppleColor RGB Card Emulation (//jse)
Now supports a bunch of the mostly non-standard video formats found on the AppleColor RGB card, including 16 color text, 16 color hires mode, and mixed black and white and color double hires
-
Machine selection
You can now select between original, autostart and plus Apple ][s, and unenhanced and enhanced //es.
Updates (2013-07-04)
-
RAMFactor Emulation (//jse)
I now simulate having a 1 Megabyte RAMFactor card in slot 2.
-
Thunderclock Emulation
There is cursory emulation of the Thunderclock card, enough to keep ProDOS applications from asking you to enter the date all the time. ProDOS attempts to guess the year from the month, the day and the day of the week, something that needs to be patched every 6 years. This means newer versions think it's 1996, older versions are stuck in the 80s.
-
Firefox Nightly Joystick Support
Joystick support has yet to officially land, but the latest nightlies support the gamepad API.
Updates (2013-03-20)
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Animation Frames
I've switched from using setInterval() to requestAnimationFrame() where supported. This, in conjunction with the graphics re-write, seems to smooth performance and provide a more stable CPU speed.
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Graphics Re-Write
This (third) re-write of the graphics system should improve performance with graphics intensive programs. Rather than rendering each graphics update as it happens, updates are rendered each animation frame.
Updates (2013-03-12)
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Apple //e
After much flailing, and much staring at MMU emulation code in despair, I've finally published my Apple //e emulator. It's probably a little more rough than I'd hoped, but it has a lot of features that I really wanted to get into it, like basic double hires support, and it uses the enhanced Apple //e ROMs.
Updates (2013-02-25)
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Joystick Support
Chrome only so far, the nascent gamepad API has finally allowed me to add basic joystick support. I can now re-live my glory days of Skyfox.
-
Re-written CPU emulator
I finally got around to applying some of the many lessons I learned along the way writing my first CPU emulator in Javascript. The last re-working gave me about a 100% performance gain.
-
Finally Fixed Oregon Trail
This seems to have been a major disappointment for many people. I was able to make it as a banker, but I'm embarassed to reveal my score.
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Competition
Now in addition to Gil Megidish's Apple2JS, there's a couple of new kids on the block, including David Caldwell's Apple II+ emulator where he's put a lot more thought into the graphics rendering than I have, and appletoo, which I just stumbled across while looking for David's emulator and haven't had much time to look at.
Requirements
-
A Browser with HTML5 Support
The most recent versions of Google Chrome, Safari, Firefox, and Opera all seem to work reasonably well these days,although variations in HTML5 support pop up, and occasionally a major release will move things around out from under me. IE prior to 9 lacks canvas tag support and is unsupported. IE 9+ renders nicely on a modern machine.
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Basic Knowledge of the Apple ][
If you don't know how to use an Apple ][, this won't be much fun for you.
Acknowledgements
-
I'm using the following libraries:
- jQuery and jQuery UI
- Base64 Utilities via KvZ
- LED graphics from Modern Life.
- CFFA2 Firmware by Chris Schumann, Rich Dreher and Dave Lyons
-
I heavily referenced:
- Beneath Apple DOS by Don Worth and Pieter Lechner
- Inside the Apple //e by Gary B. Little
- DOS 3.3 Anatomy
- Apple II Disk Drive Article by Neil Parker
- 6502.org
- The comp.sys.apple2.programmer FAQ
- Understanding the Apple ][ and Understanding the Apple //e by Jim Sather.
- Apple II Colors by Robert Munafo.
-
And special thanks to:
- ADTPro for allowing me to pull some of my circa 1980 programming efforts off some ancient floppies.
- KEGS, because at some point I got so tired of futzing with ADC/SBC code I just ported the KEGS C code for those opcodes to Javascript so I could stop worrying about it.
- Apple II History, for a lovely, informative site.
- Gil Megidish, for the kick in the pants to finally post my version, once I realized there was, in fact, another apple2js in the world.
- AppleWin, whose source code is a goldmine of useful references.
- Zellyn Hunter and a2audit, for allowing me to get really nitpicky in my memory emulation.
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Contributors
- Snapperfish Various fixes