What is this?
Apple ][js and
Apple //jse
are Apple ][ and Apple //e emulators written entirely in JavaScript
and HTML5.
Source code at
https://github.com/whscullin/apple2js
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.
Performance
In particular, the screen no longer redraws as quickly as possible.
Drag and Drop
Disk images can be dragged into the window to load them.
Contributions
Thanks to Ian Flanigan for
additions to improve ChromeBook behavior.
Updates (2017-10-08)
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)
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.
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)
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)
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.
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.
In updating this section I realized just how long
I've been doing this, since I used to have to specify Firefox 3+ and
Google Chrome 5+, and I'm now running Chrome 23 and Firefox 19.
Basic Knowledge of the Apple ][
If you don't know how to use an Apple ][, this won't be much fun for
you.
Known Limitations
Lame Audio
Apple ][js
is written entirely using HTML5 and JavaScript, so I've avoiding using
any Flash audio plugins. Most reputable browsers
now provide some sort of audio API, but no standard really seems to have
emerged. I should probably add a volume control.
Poor Printer Support
I currently only support sending text characters to a separate window.
Acknowlegements
-
I'm using the following libraries:
-
I heavily referenced:
-
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.
Contact