Build Status Release License: BSD-Clause Contributors

This is an emulator for the Commander X16 computer system. It only depends on SDL2 and should compile on all modern operating systems.

Features

Missing Features

Binaries & Compiling

Binary releases for macOS, Windows and x86_64 Linux are available on the releases page.

The emulator itself is dependent only on SDL2. However, to run the emulated system you will also need a compatible rom.bin ROM image. This will be loaded from the directory containing the emulator binary, or you can use the -rom .../path/to/rom.bin option.

WARNING: Older versions of the ROM might not work in newer versions of the emulator, and vice versa.

You can build a ROM image yourself using the build instructions in the [x16-rom] repo. The rom.bin included in the latest release of the emulator may also work with the HEAD of this repo, but this is not guaranteed.

macOS Build

Install SDL2 using brew install sdl2.

Linux Build

The SDL2 development package is available as a distribution package with most major versions of Linux:

Type make to build the source. The output will be x16emu in the current directory. Remember you will also need a rom.bin as described above.

WebAssembly Build

Steps for compiling WebAssembly/HTML5 can be found here.

Starting

You can start x16emu/x16emu.exe either by double-clicking it, or from the command line. The latter allows you to specify additional arguments.

Run x16emu -h to see all command line options.

Keyboard Layout

The X16 uses a PS/2 keyboard, and the ROM currently supports several different layouts. The following table shows their names, and what keys produce different characters than expected:

Name Description Differences
en-us US [`] ⇒ [←], [~] ⇒ [π], [\] ⇒ [£]
en-gb United Kingdom [`] ⇒ [←], [~] ⇒ [π]
de German [§] ⇒ [£], [´] ⇒ [^], [^] ⇒ [←], [°] ⇒ [π]
nordic Nordic key left of [1] ⇒ [←],[π]
it Italian [\] ⇒ [←], [|] ⇒ [π]
pl Polish (Programmers) [`] ⇒ [←], [~] ⇒ [π], [\] ⇒ [£]
hu Hungarian [\] ⇒ [←], [|] ⇒ [π], [§] ⇒ [£]
es Spanish [|] ⇒ π, \ ⇒ [←], Alt + [<] ⇒ [£]
fr French [²] ⇒ [←], [§] ⇒ [£]
de-ch Swiss German [^] ⇒ [←], [°] ⇒ [π]
fr-be Belgian French [²] ⇒ [←], [³] ⇒ [π]
fi Finnish [§] ⇒ [←], [½] ⇒ [π]
pt-br Portuguese (Brazil ABNT) [\] ⇒ [←], [|] ⇒ [π]

Keys that produce international characters (like [ä] or [ç]) will not produce any character.

Since the emulator tells the computer the position of keys that are pressed, you need to configure the layout for the computer independently of the keyboard layout you have configured on the host.

Use the F9 key to cycle through the layouts, or set the keyboard layout at startup using the -keymap command line argument.

The following keys can be used for controlling games:

Keyboard Key NES Equivalent
Ctrl A
Alt B
Space SELECT
Enter START
Cursor Up UP
Cursor Down DOWN
Cursor Left LEFT
Cursor Right RIGHT

Functions while running

On the Mac, use the Cmd key instead.

GIF Recording

With the argument -gif, followed by a filename, a screen recording will be saved into the given GIF file. Please exit the emulator before reading the GIF file.

If the option ,wait is specified after the filename, it will start recording on POKE $9FB5,2. It will capture a single frame on POKE $9FB5,1 and pause recording on POKE $9FB5,0. PEEK($9FB5) returns a 128 if recording is enabled but not active.

BASIC and the Screen Editor

On startup, the X16 presents direct mode of BASIC V2. You can enter BASIC statements, or line numbers with BASIC statements and RUN the program, just like on Commodore computers.

SD Card Images

The command line argument -sdcard lets you attach an image file for the emulated SD card. Using an emulated SD card makes filesystem operations go through the X16's DOS implementation, so it supports all filesystem operations (including directory listing though DOS"$ command channel commands using the DOS statement) and guarantees full compatibility with the real device.

Images must be greater than 32 MB in size and contain an MBR partition table and a FAT32 filesystem. The file sdcard.img.zip in this repository is an empty 100 MB image in this format.

On macOS, you can just double-click an image to mount it, or use the command line:

# hdiutil attach sdcard.img
/dev/disk2              FDisk_partition_scheme
/dev/disk2s1            Windows_FAT_32                  /Volumes/X16 DISK
# [do something with the filesystem]
# hdiutil detach /dev/disk[n] # [n] = number of device as printed above

On Linux, you can use the command line:

# sudo losetup -P /dev/loop21 disk.img
# sudo mount /dev/loop21p1 /mnt # pick a location to mount it to, like /mnt
# [do something with the filesystem]
# sudo umount /mnt
# sudo losetup -d /dev/loop21

On Windows, you can use the OSFMount tool.

Host Filesystem Interface

If the system ROM contains any version of the KERNAL, and there is no SD card image attached, the LOAD ($FFD5) and SAVE ($FFD8) KERNAL calls (and BASIC statements) are intercepted by the emulator for device 8 (the default). So the BASIC statements will target the host computer's local filesystem:

  LOAD"$
  LOAD"FOO.PRG
  LOAD"IMAGE.PRG",8,1
  SAVE"BAR.PRG

Note that this feature is very limited! Manually reading and writing files (e.g. OPEN in BASIC) is not supported by the host filesystem interface. Use SD card images for this.

The emulator will interpret filenames relative to the directory it was started in. On macOS, when double-clicking the executable, this is the home directory.

To avoid incompatibility problems between the PETSCII and ASCII encodings, you can

Dealing with BASIC Programs

BASIC programs are encoded in a tokenized form, they are not simply ASCII files. If you want to edit BASIC programs on the host's text editor, you need to convert it between tokenized BASIC form and ASCII.

Using the KERNAL/BASIC environment

Please see the KERNAL/BASIC documentation.

Debugger

The debugger requires -debug to start. Without it it is effectively disabled.

There are 2 panels you can control. The code panel, the top left half, and the data panel, the bottom half of the screen. You can also edit the contents of the registers PC, A, X, Y, and SP.

The debugger uses its own command line with the following syntax:

Statement Description
d %x Change the code panel to view disassembly starting from the address %x.
m %x Change the data panel to view memory starting from the address %x.
b %s %d Changes the current memory bank for disassembly and data. The %s param can be either 'ram' or 'rom', the %d is the memory bank to display.
r %s %x Changes the value in the specified register. Valid registers in the %s param are 'pc', 'a', 'x', 'y', and 'sp'. %x is the value to store in that register.

The debugger keys are similar to the Microsoft Debugger shortcut keys, and work as follows

Key Description
F1 resets the shown code position to the current PC
F2 resets the 65C02 CPU but not any of the hardware.
F5 is used to return to Run mode, the emulator should run as normal.
F9 sets the breakpoint to the currently code position.
F10 steps 'over' routines - if the next instruction is JSR it will break on return.
F11 steps 'into' routines.
F12 is used to break back into the debugger. This does not happen if you do not have -debug
TAB when stopped, or single stepping, hides the debug information when pressed

When -debug is selected the STP instruction (opcode $DB) will break into the debugger automatically.

Effectively keyboard routines only work when the debugger is running normally. Single stepping through keyboard code will not work at present.

Forum

https://www.commanderx16.com/forum/

Wiki

https://github.com/commanderx16/x16-emulator/wiki

License

Copyright (c) 2019-2020 Michael Steil <mist64@mac.com>, www.pagetable.com, et al. All rights reserved. License: 2-clause BSD

Release Notes

Release 38 ("Kyoto")

Release 37 ("Geneva")

Release 36 ("Berlin")

Release 35

Release 34

Release 33

Release 32

Release 31

Release 30

Emulator:

Release 29

Release 28

Release 27

Release 26

Release 25

Release 24

Release 23

Release 22

SYS65375 (SWAPPER) now also clears the screen, avoid ing side effects.

Release 21

Release 20

Release 19

Release 18

Release 17

Release 16

Release 15

Release 14

Release 13

Release 12

Release 11

Release 10

updated KERNAL with proper power-on message

Release 9

Release 8

Release 7

Release 6

Release 5

Release 4

Release 3

Release 2

Release 1