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Revision as of 19:55, 7 April 2017 by Blackystardust (talk | contribs) (Removed native os/2 items)
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Prime Directive

  • when adding/changing stuff that needs (G)UI items/changes, add a proper entry to the Developer_log to notify the UI maintainers.
  • when changing something that needs an update to text messages (and as such, the translation), add a proper entry to the Translator_log to notify the Translators.
  • when adding/changing command-line options and/or resources, adding a new feature or change the behavior of an existing feature, please update the documentation :)
  • after fixing a bug or implementing a new feature, update its status on the Bug Tracker and mark it as fixed in the list below.
<@_tlr> Please at least test the issue you were trying to fix before committing.

Known Issues

This is the list of known problems. also look at Tracker: open Bugs

This list always refers to the status of the last major release version, which was 3.0. Items that have been fixed by the time of a major release will be removed, items fixed after that will be marked as fixed and stay until the next major version. New items will be added as noticed.


MAN Pages

  • the man pages are very outdated and should perhaps be generated from the infotext
    • the man pages refer to the path where the html documentation can be found, this should get adjusted to whats actually used
  • the following man pages are missing: vsid
  • man pages for the individual emulator binaries should get installed as symbolic links to vice.1


  • many nodes are not yet linked correctly, which makes some of the exporters output garbled and/or suboptimal output (windows .hlp, unix .info).
Workaround: use the .html or .pdf documentation, which is exported correctly.

The documentation is partly outdated and/or incomplete, in particular:

  • some info that was previously hidden in target specific articles on the VICE knowledge base should get merged into vice.texi - the remaining articles are here
  • some descriptions of emulator formats are missing (D67, D1M, D2M, D4M...)
  • descriptions of several snapshot modules are missing (Plus4, TED...)
  • generate target specific documentation
    • win32 documentation. (.chm format)
    • amiga documentation. (.guide format)
    • BeOS documentation.
    • MSDOS documentation. (.txt format)
    • OS/2 documentation. (.inf format)
    • RiscOS documentation.
    • SDL documentation.

for details look at doc/Documentation-Howto.txt


  • many test programs (mostly for vic20) are not yet integrated into the automatic testing
  • TODO: fix the reference screenshots and/or the scripts so they dont rely on the "normal" rendering mode anymore
  • TODO: make a test program to determine visible screen dimensions



  • Support for more languages.
  • Translation support for BeOS.
  • Translation support for MSDOS


  • When a key which is shifted on the real machine but unshifted on the PC or Unix keyboard you are using is pressed, the virtual shift is pressed together (i.e. at the same clock cycle) with the main key; this could not work with some keyboard routines.
note: also see this knowledgebase article
Workaround: If you have to use the function keys, press the (real) shift key manually (e.g. F2 = Shift + F1, F4 = Shift + F3 and so on); this also works with other keys.
  • When typing very quickly, some keypresses might get lost. This comes from the fact that the keyboard is (and can not) be scanned in real time (ie every 1mhz cycle). Even if we could remove the per frame scanning from the emulator itself, the operating system and last not least the keyboard itself would still impose a certain limit (something like 10ms for USB HID keyboards, for example). That means if a key is pressed and released within that timespan, the emulator does (and can not) know about it.
Workaround: the only workaround is to type slower, it cant be fixed.
  • Some ports/emulators/keyboard-types do not have all required keymaps (and a fallback will used) - look at Keymaps for details
  • Although "shift lock" can be mapped to a key, not all ports and/or emulators support it due to missing keymaps and/or implementation details.
TODO: check ports and fix or at least add a comment in the keymaps
  • contact-bounce is not emulated
TODO: make a proper test program


TODO: make a proper test program

Joystick port devices

  • Paperclip 64 dongle emulation is broken


  • some options where the available parameters depend on the machine type lack proper descriptions (-drivetype)


  • When loading a snapshot, the monitor break/watchpoints break.

History Recording

  • history recording currently breaks on a lot of user actions, such as using autostart or attaching a cartridge.
Workaround: make sure to start up with a bog standard c64, and then load/run the program in question manually

note: since history recording is very error prone and hard to debug, we depend on feedback (on either failure or success) on this topic very much. if you still have problems with the current release, please report them including testcases.

Screenshots / Media Recording

  • Screenshots with activated video filter (CRT emulation / Scale2x) do not deliver the expected (filtered) result.


  • some things are still shared by videochips although they shouldnt be, resulting in conflicts for eg the color generation (visible in x128 in ports that show two windows at a time, when crt emulation is enabled, eg adjusting brightness affects also the other window)
  • TODO add a 4:3 fixed aspect ratio scaling mode
  • TODO when a test program has been written, adjust the "normal" border mode accordingly (CAUTION: fix testsuite first)
  • TODO put all border mode parameters into arrays, make a global function to query the parameters and modes (for UIs) and then add "TV" mode (like "normal", but not centered)
CRT Emulation
  • the rf-modulator output characteristics are not emulated, which means the so called "black bleeding" effect does not work (emusux0r,
  • artefact color and luma/chroma crosstalk are not emulated (eg the "red/green stripes")
  • color generation should get a partial rewrite according to new research by pepto (

see for some further info on this topic.

Drive Emulation

  • Dual disk drive 2040/3040 support (DOS1, 670 blocks free) is not working
  • when using a dual drive, and no TDE, only the first drive (0:) can be used.
  • G64 image support is incomplete, the speedzone definitions are completely ignored
Note: this is no problem in practise, so far not a single title (game) could be located that would actually require this kind of support to work. Incase you find a program that needs this kind of support, please let us know.
  • RPM and Wobble settings have currently no effect when P64 images are used
virtual Devices
  • handling of CBM style sub partitions is incomplete, write operations on sub partitions may give unexpected results.
  • RELative files are only supported when using disk images ( )
  • support for double sided disk images is very shaky, since no concept of disk sides exists and the tracks on the second side are referenced by an offset into the image, the handling of images with different number of tracks is needlessly hard and complicated (and thus broken).
True Drive Emulation
  • serial timing latency is not implemented. due to their physical properties, it takes about half a cycle for a value to show up at the respective output pin after it has been written to the register. and respectivly, it takes about half a cycle from changing an input pin until the value in the respective register changes.
  • mechanical delays (such as head stepping and motor spinup) are not emulated yet.
  • accessing device #7 on the IEC bus works (only real devices), but it only works if True Drive Emulation is OFF, even though this has nothing to do with drives. This needs to be fixed in TDE somehow.
  • 1541 Emulation still fails a few test programs
  • 2mhz mode of the 1571 is not handled correctly
    • drive CPUs always run at 1Mhz for all drives (hardcoded 1000000 at a few places)
    • 1571 has extra delay on on reading sync inside the drive, ("you cannot use BVC in 2mhz mode!")
  • 1571CR emulation does not work correctly
  • double sided 1571 images do not work correctly
    • regular (70 tracks) vs extended (80 or 84 tracks) d71 images are not handled at all (vdrive problem)
    • creating (formatting) G71 does not work correctly, the second BAM block will be wrong (vdrive problem)
    • double sided P64 can be used, but can not be created from within VICE (see patch #122, r32586). since these are non existant "in the wild" and probably not needed for anything - not a big problem :) to handle this properly, a seperate image format should get created (at least internally)
Dual Drives

r25459 by Rhialto:

I enabled up to DRIVE_NUM IEEE-488 drives, rather than 2 (in True Drive Emulation mode). In some places where they are enumerated, it is 4. The drives use their full 3 bits of jumpered drive number now, rather than just 1 bit.

I have also generalised code so as to allow another dual drive. Since dual drives currently use up two device numbers, it will use 10 and 11. I'm currently simplifying the methods for checking the dualness of a drive.

When that is done, I hope to have gained enough understanding of the code to remove the horrible hack of using 2 devices for a dual drive, and remove it. It looks like it will simplify a lot of code (including removing lots of code that I changed for allowing 2 dual drives). That will have some repercussions on the GUIs, since for every drive you may need to be able to attach two image files. It also would add an extra "drive" parameter (in addition to the current "unit" parameter) to a shedload of functions, although this is a pretty mechanical change. In fact, it is the GUI change that currently holds me back...

TODO: Think of some elegant way to represent settings for 8 floppy images (for 4 dual drives), without requiring all GUIs to be updated at once.

TODO: After that, I can rework the code to make dual drives more regular and hence allow 4 of them.

  • when using dolphin dos 3 emulation, the state of the mc6821 is not saved to/restored from snapshots
  • when using supercard+ emulation, the optional additional index hole sensor (for the IHS nibbler) is not emulated
Drive Noise
  • since the current implementation is a very simple sample player, things like "drive composer" will not work

Datasette Emulation

  • unlike with a real datasette, the emulated counter will stop counting when no tape/image is present
  • when a t64 image is attached, the datasette status will incorrectly say "no image".
Note: since t64 is currently only accessable via kernal traps, the datasette emulation actually treats this case as if no image is present. The respective code must be updated so the datasette emulation actually "knows" about when t64 is in use.
2016-10-20: This appears to have been fixed in at least the Gtk and Xaw ports: when hovering the mouse over the datasette status widget the image name is displayed in a 'tooltip'. (Bas Wassink)
  • motor noise is not emulated

Tape port devices

  • DTL Basic Dongle emulation is broken

Printer Emulation

there perhaps should be a way to explicitly set a directory for printer output files Gpz 01:24, 4 July 2011 (UTC)
  • printer noise is not emulated
  • printers don't work on the PET (or other IEEE-488 computers)


unfortunately to fix this a lot of c1541 will have to be rewritten (mount image only once, not for each operation) Gpz (talk) 23:57, 13 December 2012 (UTC)



  • the case when CIA1 port A and port B are both in output mode, port A outputs low, port B outputs high, both are connected via the keyboard matrix and a value is read from port B is not handled correctly ( testprogs/CIA/ciaports ; ) (has been improved but is not perfect)
  • the various analog side effects that must be considered when pressing two or more keys are not emulated correctly, so this will currently not produce the correct results in some corner cases.
  • Shift Register IRQ triggers only cycle too early (see this bug)
  • I/O "peek" function is broken

used in: C64, C128, 1570/71


  • the POTX/POTY sampling period is not taken into account (512 cycles)
  • POTX/POTY sampling jitter is not emulated
  • only one mouse or pair of paddles can be emulated at a time
  • 'dump' support in the monitor is missing

used in: C64, C128, CBM2, (VIC20, PLUS4, PET: SID cart)


used in: Plus4


  • Some basic features of the VDC are missing:
  • Registers 34/35 (horizontal blanking position) not implemented
  • $d600 bit 7 STATUS flag is always set, ie. the VDC is never 'busy'. Fixing requires emulating the internal timing of the VDC..
  • Differences between 8563 and 8568 are not all emulated, eg. register 38
  • Snapshot doesn't include VDC
  • Clock calculation for lightpen is incorrect

used in: C128


used in: VIC-20


used in: C64, CBM2


  • The test bit is not emulated, which results in things like 'real interlace' ([1]) and the $D030 new VIC-IIe color palette hack ([2]) not working.

used in: C128


  • 48bit frames support is incorrect/broken
  • synthesizer condition 2 loss-effect-, shape- and repeat- bits have no effect
  • reading from the speach rom is not emulated (which is not really an issue since neither magic voice nor v364 have one)
  • snapshot support is missing

used in: Magic Voice, Plus4 (V364)


  • interrupts are not implemented
  • implementation of C2 output modes is incomplete

used in: Formel64, Magic Formel, Dolphin-DOS 3


  • snapshot support is missing

used in: RR-Net/TFE


  • I/O "peek" function is broken
  • I/O "dump" function is missing

used in: 2040/3040/4040/1001/8050/8250


  • I/O "dump" function is missing

used in: FD4000/FD2000


  • I/O "dump" function is missing

used in: 1570/1571/1581



  • snapshot support is missing

used in: MMC64, MMC Replay


  • snapshot support is missing

used in: MMC Replay


  • snapshot support is missing

used in: C64, VIC-20



x64 / x64sc

  • the memory layout for "Max Machine" is not yet correct
  • when SX-64 is selected, the tick for the CIA TOD clocks should always be 60Hz (regardless of PAL/NTSC)
  • for details see C64models
x64 issues addressed by x64sc

To clarify... these will never (as in can't) be emulated in the regular x64, unless we end up replacing x64 with x64sc.

  • some VIC-II bugs present in the old VIC-II core
    • inline gfx data changes are not emulated (see testprogs/VICII/gfxfetch/)
    • The VIC-II implementation lacks cycle exact sprite collision support
    • VIC-II shows wrong colors when switching from hires background to idle with borders open (see testprogs/VICII/border/*, Krestology)
    • VIC-II fetches from cartridge in ultimax mode can not be emulated properly for all carts

note: this is also broken in xcbm2

Workaround in all cases: use x64sc :)

x64 specific problems

note: While most of the x64sc improvements/fixes are impossible to shoehorn into x64 (hence the split), a few things could still be improved:

Workaround in all cases: use x64sc :)

Cartridge System
  • some carts have no snapshot support yet (still broken: MMC64, Magic Voice, MMC Replay, MIDI, RR-Net MK3, Ethernet.)
    • IDE64 & ATA system can only handle "readonly" snapshots now. Somehow the image file must be matched to the snapshot to prevent corruption.
  • some carts do not work 100% yet (still broken: Magic Voice, MMC Replay.)
    • Magic Voice: emulation of the speech chip is incomplete (see Todo#t6721a), this breaks some words included in the magic voice rom and the "a-bee-c" cartridge. Memory mapping is incomplete/broken (which however affects no known software/testcase).
    • MMC Replay: only the BIOS mode works right now; the monitor may incorrectly access cartridge memory (even) if "bank cart" is explicitly set
    • RR-Net MK3: to get the ethernet functionality it must be explicitly enabled too, and will appear as a "clockport" internally (which is wrong)
  • the (very strange, and incompatible with most cartridges) passthrough port of the SFX sound expander is not emulated
  • various cartridges have no support for verbose i/o dump in the monitor
  • Passthrough port functionality depends on ordering of cartridge attaches, especially visible from the command line. (e.g. MMC64+RR ok, RR+MMC64 not)

note: the detailed todo list/status is here.


  • Support for fast mode (2MHz) is implemented but incomplete, detailed information about the stealing of cycles by the VICII when switching back from fast mode is missing and therefor the emulation of it is incorrect.
  • support for c128 specific expansion port handling/mapping is missing in the c64/c128 cartridge system (MMC Replay, FastLoad128, MACH128, other?)
  • the relative speed and details like cycle-stealing of the z80 is inaccurate ( ) TODO: cycle accurate test programs
  • CPU history (chist) implementation is incomplete



The DTV emulator is very inaccurate and is in need of a partial rewrite. Maintainer wanted!


The plus4 emulator is generally work in progress and not yet "ready". Maintainer wanted!


  • The CBM-II emulator, when the execution bank is set to an open memory bank, sets the zeropage and stack access to unmapped, but actually existing memory. This is a bug but cannot be avoided with the current CPU code architecture.
  • break- and watchpoints in zeropage are broken. this is because of the old cpu core, and can likely not be fixed without migrating to the new one.
  • banking in the monitor is broken
  • breakpoints are broken
    • when a breakpoint is hit, the monitor disassembles from the wrong bank
    • breakpoints will only hit in the bank which is active in the monitor (!)
  • when running the burn-in diagnostic tests, the CIA is reported as bad ( )
note: run like this: xcbm2 -model 610 -ntsc -drive8type 8050 -virtualdev +truedrive -8 cbm2-burnin.d80
  • CPU history (chist) implementation is incomplete


  • The emulator, when the execution bank is set to an open memory bank, sets the zeropage and stack access to unmapped, but actually existing memory. This is a bug but cannot be avoided with the current CPU code architecture.
  • break- and watchpoints in zeropage are broken. this is because of the old cpu core, and can likely not be fixed without migrating to the new one.
  • banking in the monitor is broken
  • In the C510 emulation the VIC-II timing is not exact, i.e. the stopping of the CPU during bad lines is wrong.
  • The C510 emulation uses the old VIC-II core which means no cycle exact sprite collisions, no inline gfx changes, and probably more.
  • CPU history (chist) implementation is incomplete


  • When running the "8296d diagnostic" test of the 8296 system disk on "xpet -model 8296" some tests fail:
    • when TDE is enabled, the program will hang. when TDE is disabled, the IEEE interface status will be reported as bad
    • the userport is reported as bad (perhaps some dongle is needed?)
note: run like this: "xpet -model 8296 -drive8type 8050 -8 8296d-systemdisk.d82 -editor edit-4-80-b-50Hz.901474-04.bin". the "burnin8296" program seems to be an older version of the "8296d diagnostic" program. it runs when TDE is enabled, but the 50Hz irq test fails.
  • break- and watchpoints in zeropage are broken. this is because of the old cpu core, and can likely not be fixed without migrating to the new one.
  • some combinations of selected keymap and keyboard model do not work because of missing keymaps
  • CPU history (chist) implementation is incomplete

Ports / UIs

  • Make a list of Hotkeys used per port, compare and try to make them the same / alike. ( Hotkey cleanup )
  • enable/disable menu items in drive settings menu according to Drive_options_precedence
  • Fix all Keymap handling according to Keymaps
  • VSID is not fully supported in all ports: dos, OSX
  • YUV rendering (used by amiga morphos and XAW) implementation is incomplete
    • scale2x not available
    • some renderers are missing
    • doublesize + y-stretch (2x4) doesnt work correctly


The windows GUI has a lot of inconsistencies and really needs at least a partial re-write. Maintainers wanted!

Win32 DX9
  • There is a bug when moving the window partly outside the left edge of the screen. The rendered contents seem to "lock" to the left border. This seems to depend on the driver of the gfx adapter as is only shows on some machines.
Windows 7
Windows XP and up
  • Running as an unprivileged user causes a heap of problems. VICE tries to write log files and settings to the directory the VICE binary is located. This will obviously fail when running as an unprivileged user. The proper way to handle this is to add a function `archdep_home_path()` to src/arch/win32/archdep.c and use that to determine where to place log files, settings, etc. Most/all other ports use this.

X11 (XAW and GTK)

  • The custom TextField widget is buggy and can cause crashes on DEC/Alpha machines, and possibly on other systems too. If you get weird X protocol errors or the file selector makes the emulator die when you close it, this might be the cause.
    Workaround: recompile with the `--disable-textfield' option. If it still does not work, please tell us.
  • some text output may show broken characters for "foreign" UTF8 chars due to improver conversion (please report such cases!)
  • the initial window and canvas should be created using its final size and not resized later
  • lightpen coordinates are not accurate when using vidmode for fullscreen
  • mouse warping when using vidmode for fullscreen is buggy
  • the mouse pointer is incorrectly un-grabbed when switching from/to fullscreen with the mouse- or lightpen emulation enabled.
Workaround: use XRandR for fullscreen
  • Gnome/GTK+ commandline options must come first (before any non-options)
  • the event handling is buggy, which results in some more or less broken behaviour eg when holding down ALT-D or ALT-B (the later in fullscreen mode)
  • add Session Management
  • improve Tape status widget, (.TAP vs .t64 handling is lousy.)
  • implement actual Monitor GUI (like in the windows port) ( )
  • create a "open cartridge image" dialog allowing selection of any (bin) cartridge type and preview of .crt file info
  • gtkglext is not ready yet for GTK3, so hardware scaling will not work yet
  • the window is resizeable even when hardware scaling is not enabled
  • Some DEC/Alpha machines crash due to the XAW implementation.
    Workaround: Compile VICE with GNOME support `--enable-gnomeui' instead.
  • warning "Files using this header must be compiled with _SVID_SOURCE or _XOPEN_SOURCE" may show up if none is defined in the environment
    Workaround: define _XOPEN_SOURCE=600 on the commandline
  • Context popup menu for drive attach is broken if more than two drives are active.
  • when hardware rendering is enabled, greenish color might appear around the drawing area.
  • Aspect ratio/scaling is broken in fullscreen mode when hardware rendering is enabled (canvas is always stretched to fill the entire screen)
  • the mouse pointer is incorrectly un-grabbed when switching from/to fullscreen with the mouse- or lightpen emulation enabled.
  • mouse- and lightpen emulation/coordinates are broken on the second window (VDC/x128)
  • add "commandline options" help window (like in the windows port)
    Is available in trunk, but lacks scrollbars, so scrolling through the text requires to user to click inside the window and scroll with keys (Compyx 2016-12-20)
  • hide hidden files (dot files) in the filebrowser ( )
  • implement "edit" (copy/paste) menu
  • add Drag'n'Drop support
  • the status bar area of the created window is larger than it should be
  • ffmpeg half frame-rate setting missing in "save media image" dialog (FFMPEGVideoHalveFramerate)
  • sound volume can not be changed using the GUI (SoundVolume)
  • datasette status widget is not implemented


the OSX port is somewhat outdated and needs fixing badly - Maintainer wanted!

  • ADD: the VSID GUI is missing and needs to be implemented
  • FIX: the xcbm5x0 and xcbm2 GUI should separated properly (eg in resource inspector)
  • FIX: the xscpu64 GUI is broken
    • copy from c64 UI, except for tape, no freezer cartridges
  • FIX: long overdue rework of keyboard map handling is in trunk now. for details on migrating to the new code see Keymaps (r29610)
  • FIX: new joyport system. The new system makes things modular. On one side you have the devices that can be on a joyport, and all the code for those has to do is handle reading/writing of digital lines and reading of the pot-lines. On the other side you have the 'chip' emulations that deal with the hardware emulation. The new system handles the traffic between the two sides, handles conflicts between input resources that devices use and provides a way for the gui's to query what devices are present (name and id). (r29938)
    • new resources related to the new joyport system: "JoyPort1Device" (int), "JoyPort2Device" (int), "JoyPort3Device" (int) and "JoyPort4Device" (int)
  • FIX: the joystick settings dialog is broken
  • FIX: joystick/mouse stuff is broken in resource inspector too
  • FIX: Removed "UserportJoyType", "JoyDevice4" and arch joystick device 4 related resources in x64dtv. (r30294)
  • ADD: mouse init/shutdown calls to xcbm2 and xpet. (r30161)
  • FIX: Check and test UI items for Atari ST mouse, Atari CX-22 trackball, Smart Mouse. testprograms can be found in testprogs/propmouse
  • ADD: model selection for xplus4 is missing (r24285)
look at plus4/plus4model.h for models and functions, it works just like the c64 counterpart
  • ADD: model selection for x64dtv is missing (r24287)
look at c64dtv/c64dtvmodel.h for models and functions, it works just like the c64 counterpart
  • ADD: model selection for xcbm2/cbm5x0 is missing (r24326)
look at cbm2/cbm2model.h for models and functions, it works just like the c64 counterpart
  • ADD: model selection for x128 is missing (r25052)
look at c128/c128model.h for models and functions, it works just like the c64 counterpart
  • ADD: model selection for xvic is missing (r26968)
look at vic20model_get/vic20model_set for models and functions, it works just like the c64 counterpart
  • ADD: 3rd sid support for x64 and x128 (r24733).
    • changed Resource: "SidStereo", instead of 0=off, 1=on, it's now: 0=off, 1=1 extra sid, 2=2 extra sids.
    • new Resource: "SidTripleAddressStart", the address of the 3rd sid.
  • ADD: Printer 6 (Plotter) is now available, a new menu like the existing printer menus should be added which has "1520" and "RAW" in its driver selection (r27914)
  • ADD: accessing device #7 on the IEC bus works (only real devices), respective selection (0: none 2: real) should get added to the menus (r28014)
  • ADD: new function "cartridge_get_info_list()" for querying the list of cartridges for building the "attach binary image" menu(s) in x64/x64sc/xscpu64/x128. see cartridge.h (r28982) convert code to use the list instead of hardcoding it
  • ADD: new API to query list of palettes, see palette.h, use this to create the palette menu(s) at runtime. (r30708)
  • ADD: added generic function/list for querying the enabled compile time features. (see vicefeatures.h) (r28935), this info should be shown in a dialog near the "about/help" stuff
  • FIX: cartridge_attach_image(type,name) and cartridge_detach_image(type) are now available in xcbm2/cbm5x0, look for types in cartridge.h, direct usage of "Cart1Name", "Cart2Name", "Cart3Name", "Cart4Name" resources is deprecated, use the above functions instead. (r24210)
  • FIX: ui_pause_emulation is not implemented (see r29876). when that is done "advance one frame" when in pause mode can be added to GUI.
  • FIX: check and fix in vicemachinecontroller.m, changed mon_reg_list_t->flags into a bitfield (see mon_register.h) (r28503)
  • FIX: updated the datasette emulation to also work as expected when there is no tape image present
    • all UI elements should be always visible and enabled (as with a real datasette :))
    • the parameter passed to ui_set_tape_status can then be used to somehow indicate whether a tape image is present (eg by using a different color)
    • ui_set_tape_status, ui_display_tape_motor_status, ui_display_tape_control_status and ui_display_tape_counter in ui code perhaps must be updated to handle being called before the respective gui item has been created (which unfortunately can not be avoided easily with the current architecture)
  • FIX: X64->Help->If you click on Contributors, you get whatever was shown last in the help menu. If nothing was shown last, it will come up with a blank screen. If the License was shown last it will show the license, or if the Warranty was shown last, it will show the warranty if you click contributors.
  • ADD: a lot of options are currently only available in the resource inspector and may be added to menus/dialogs
  • FIX: the resource inspector is incomplete/does not provide access to all resources
  • FIX: the I/O tree should get updated for other machines than C64
  • FIX: options->vicii->settings... opens an empty window
  • FIX: window->monitor window opens an empty window
  • FIX: window->debugger windows-> all dont work
  • FIX: Changed MMC64, MMCR and RetroReplay to use the new clockport system (r31947)
    • new resource "MMC64ClockPort" (int) to select the MMC64 clockport device
    • new resource "MMCRClockPort" (int) to select the MMCR clockport device
    • new resource "RRClockPort" (int) to select the RetroReplay clockport device
    • there is a list of available devices, you can get this list by including 'clockport.h' and using the 'name' and 'id' members of the 'clockport_supported_devices_t clockport_supported_devices[]' variable, the end of the list is indicated by a 'NULL' for the 'name' member and a '-1' for the id member
  • FIX: Added IDE64 clockport emulation (r31967)
    • new resource "IDE64ClockPort" (int) to select the IDE64 clockport device
    • there is a list of available devices, you can get this list by including 'clockport.h' and using the 'name' and 'id' members of the 'clockport_supported_devices_t clockport_supported_devices[]' variable, the end of the list is indicated by a 'NULL' for the 'name' member and a '-1' for the id member



  • In the MS-DOS port you have to save the configuration and restart the emulator when changing VDC double size mode.
  • ADD: real IEC device support via par port or ser port
  • ADD: proper lfn detection
  • FIX: X64->Video settings->VGA resolution->Mode 5: 640x480 8Bit crashes the emulator.
  • FIX: X64->Video settings->VGA resolution->Mode 7: 1024x768 8Bit crashes the emulator.
  • FIX: X64->Video settings->VGA resolution->Mode 11: 800x600 16Bit crashes the emulator.
  • FIX: X64->Video settings->VGA resolution->Mode 12: 1024x768 16Bit crashes the emulator.
  • FIX: X64->Video settings->VGA resolution->Mode 13: 640x480 32Bit crashes the emulator.
  • FIX: X64->Video settings->VGA resolution->Mode 16: 800x600 32Bit crashes the emulator.
  • FIX: X64->Video settings->Video Standard->Cannot select NTSC.



   NEW: Lightpen/gun emulation in x64, x128 and xvic
   Resource: Lightpen (toggle)
   Resource: LightpenType (enum, see lightpen.h)
       0=Pen with button Up (TODO: product name Atari CX75)
       1=Pen with button Left (TODO: product name?)
       2=Datel Pen
       3=Magnum Light Phaser
       4=Stack Light Rifle 
   NOTE: see SDL or win32 for driver implementation example



  • Sometimes the application loses the keyboard focus; no keystrokes are accepted inside the emu, so the emulator has to be restarted.
  • Sound problems on slower machines (P100) with a non-official driver for sb16.
  • The monitor only works if you start the emulator from a terminal; if you start the emu from tracker and enter the monitor, you are "lost"
  • Fullscreen mode is not implemented.
  • Lightpen/gun support (21132)
   NEW: Lightpen/gun emulation in x64, x128 and xvic
   Resource: Lightpen (toggle)
   Resource: LightpenType (enum, see lightpen.h)
       0=Pen with button Up (TODO: product name Atari CX75)
       1=Pen with button Left (TODO: product name?)
       2=Datel Pen
       3=Magnum Light Phaser
       4=Stack Light Rifle 
   TODO: Lightpen driver and UI items for the following ports: amiga, beos
   NOTE: see SDL or win32 for driver implementation example
  • Options->DirectWindow cannot be checked in all emulators.
    • It is checked by default if available, but not if system video driver support is missing and currently never in Haiku. I might add an error message at some point. --Loggedoubt 23:53, 22 May 2012 (UTC)
  • X64->Options->Expansion carts->magic voice options->Magic voice emulation and magic voice file cannot be checked.
  • X64->Options->Expansion carts->Easy Flash options->Save .crt file now->Error message might be better if said no .crt file attached.
  • X64->Expansion carts->MMC64 options->MMC64 emulation cannot be selected.
  • X64->settings->Drive settings->1551 shouldn't be there. (Plus4 only)
    • A symptom of a much larger problem: the drive type list isn't machine-specific at all. --Loggedoubt 15:58, 25 February 2012 (UTC)
  • XPlus4->Settings->V364 Speech options->V364 Speech emulation cannot be selected.
  • Compiling with `--enable-ethernet` fails due to absence of rawnetarch.{c,h} missing --Compyx 2016-10-26 (tested on Haiku)


  • there is no interface for browsing files inside (d64..) images
  • Drive>Fliplist settings>Add current image to fliplist>Item needs status text to show that the action has been done.
  • Drive>Fliplist settings>Remove current image from fliplist>Item needs status text to show that the action has been done.
  • Drive>Fliplist settings>Attach next image in fliplist>Item needs status text to show that the action has been done.
  • Drive>Fliplist settings>Attach previous image in fliplist>Item needs status text to show that the action has been done.
  • A better way of showing filenames (maybe using contraction) needs to be made
  • Cartridge>MMC64>Enable MMC64 can not be used unless a MMC64 ROM has been selected, it should be made inactive if not
  • improve the Android port.

External Libraries

VICE uses a few external libraries of which either header files or complete sources are included in the tree:

  • opencbm (src/opencbm.h) (
    • should get moved to src/lib/..
  • P64 (src/lib/P64)
  • ffmpeg (src/lib/libffmpeg)
    • building with `--enable-shared-ffmpeg` will fail when not root. VICE's configure triggers a build and install of liblame which tries to install into /usr/local/lib.

besides the above, other libraries are used which are currently linked dynamically and must be supplied as dlls for the windows port

  • SDL
  • zlib
  • hardsid


  • The "sc" rewrites. Migrate emulators to the cycle based CPU core (6510dtvcore.c, should be renamed), which allows:
    • cycle based hooks for complex hardware expansions (SCPU)
    • in-line graphics data change emulation (see testprogs/VICII/gfxfetch)
    • cycle exact Blitter/DMA vblank start and proper LinearA/B counter handling on x64dtv
    • cycle based drawing
  • ...and requires (at least):
    • rewrite video chip modules to use:
      • cycle based fetch/etc (VIC & VICII done, VICII-DTV in progress)
      • cycle based drawing (VICII done)
    • remove 1 clock write offsets (at least CIA/VIA already handled)
    • an insane amount of regression testing (preferably with new testprogs where needed)

New Features

This is the place for the VICE developers to put down ideas about the future development of VICE.

Some of these ideas might never be realized, and might look completely absurd, but they could be the inspiration for other ideas.

By putting these ideas down they will be known to any other developers that would like to pick up one of the ideas and implement it.

also look at Tracker: open Feature Requests


History Recording




Sound System

  • sound sync needs a rewrite, its too complex and fails a lot

Video System

  • some kind of generic interface to handle video input is required to handle scanner/digitizer type of carts

Hardware emulation



  • internal (?)
    • c64/c128 1.44 MB disk drive support. ([3])
    • c64/c128 SCSI expansion support. ([4])
  • Cartridges
    • IDE64 improvements
      • IDE64 eth64 shortbus expansion support. ([5])
      • IDE64 duart shortbus expansion support. ([6])
    • Clockport improvements
      • Silversurfer (UART) support ([7])
      • IDE64 based eth64-II support ([8])
    • Community Information Locator Commodore 64/128 addon cartridge ([9])
    • RAM Floppy (REX 9680) support
    • Daisy Sound sampler audio input support. ([10])
    • PS64 speech cartridge support. ([11])
    • Voice Messenger speech cartridge support. ([12])
    • ramlink support. ([13] [14])
    • ramdrive support. ([15])
    • turbo master cartridge support (4Mhz 65C02). ([16] [17])
    • turbo process cartridge support (4Mhz 658156). ([18] [19])
    • flash-8 cartridge support (8Mhz 65816). ([20])
    • SCPU cartridge support (20Mhz 65816). (in progress, has lead to a new emulator called xscpu64) ([21] [22]) (
    • The Final Chesscard (65c02) ([23])
    • german BTX cartridge (6809)
    • MasC=uerade Cartridge Converter support, this cart is originally intended to use c64 carts on the vic20, but in theory could also be used the other way around. ([24])
    • BI-80 cartridge support. ([25])
    • Buscard II IEEE488/printer-port cartridge support. ([26])
    • "Disk Mate" (Datel)
    • MAYA Software Eprom Cart
    • PCC-4/PCC-8 Eprom Cart (Jason Ranheim)
    • "Alien Flash"
      • VICEminus had this
    • Software of Sweden Megacart
    • DUBCRT
    • "MegaOne" - Easyflash compatible Flash cartridge, see here
  • Cartridges that wont be emulated:
    • SoftPROM cartridge ([27])
      • pointless, unless software specifically designed for this cart can be found. other than that its just an ordinary 8k game cart (with battery backed up ram instead of rom). Gpz 23:01, 30 October 2010 (UTC)
    • Net64 cartridge support. ([28])
      • this is exactly the same as "the final ethernet" (which is emulated) Gpz 23:27, 30 October 2010 (UTC)
    • 64NIC
      • again, same as TFE. also has an optional eprom, which is equivalent to using cart8
    • "GeoAction"
      • pointless, equivalent to Action Replay + GeoRAM/RamCart
    • "Flash Gordon"
      • pointless, external kernal with flash, prototype (not released)
  • Userport
    • CBM1660 (userport) modem300 support. ([29])
    • CBM1670 (userport) modem1200 support. ([30])
    • FB-RS232 (userport) support. ([31])
    • c64 p64 midi interface: ([32])
    • Scanntronik handyscanner (userport) support. ([33])
    • Video Byte II video digitizer (userport) support. ([34]) ([35])
    • Computera Eyes video digitizer (userport) support. ([36] [37])
    • Userport RocketDrive support. ([38])
    • CIA-IDE-HD support. ([39])
    • Aprotek universal rs232 adapter support. ([40])
    • Comet64 support. ([41])
    • L. Pantarottos adapter support. ([42])
  • Tape Port
  • Video output.
    • c64 LCD64 screen support. ([48])


  • c128 plus60k support.
  • c128 plus256k support.
  • c128 256K memory expansion hack support.



  • add support for "speedy" freezer cartridge


  • PET ROM-socket RTC support. ([52])
  • 8296 pet hardware ram lines connected to userport support.
  • 8296 RAMdisk 2008 support. ([53])
  • 8296 pet switchable 4 screens output support.
  • pet IEEE488 -> IDE/RS232 support. ([54])
  • High-Res Technologies Graphics Board support. ([55])
  • MTU K-1002-2 DAC sound system support. ([56])


  • cbm2 z80 support.
  • cbm2 8088 support. ([57])