Hatari User's Manual

Index

Introduction

General description

Hatari is an Atari ST, STE, TT and Falcon emulator for Linux, FreeBSD, BeOS and other Systems which are supported by the SDL library. The emulator is open source software and is distributed under the terms of the GNU General Public License (GPL).

The Atari ST was a 16/32 bit computer system which was first released by Atari in 1985. Using the Motorola 68000 CPU, it was a very popular computer having quite a lot of CPU power at that time. See Appendix B for details on emulation in general.

Unlike many other Atari ST emulators which try to give you a good environment for running GEM applications, Hatari tries to emulate the hardware of a ST as close as possible so that it is able to run most of the old ST games and demos. Of course you can run normal GEM applications with Hatari, too. Recent versions of Hatari even feature basic STE, TT and Falcon emulation.

Features

STE hardware emulation

There is support for following additional STE features:

Experimental TT hardware emulation

There is support for following additional TT features:

Falcon hardware emulation

There is support for following additional Falcon features:

See the developers' doc/todo.txt file (included with Hatari sources) for the details on the few remaining emulation gaps and the Hatari Atari Software Compatibility List for which Atari programs are known to be affected by them.

System requirements

Hatari currently has the following system requirements:

Certain versions of Hatari have successfully been tested by various people on the following systems:

Compiling and running

Compiling Hatari

First, you need the SDL library, you can get it at: http://www.libsdl.org/. Most distributions already ship a suitable version. Make sure to install the appropriate header files as well often called "libsdl-dev" or the like.

Second, you need the zLib compression library. You can get it from http://www.gzip.org/zlib/ but the version shipped with your distribution will be sufficient in most cases. Make sure to have the header files for it installed as well.

For optional features like PNG format screenshots and Hatari window embedding, you need to have the header files for libpng and libX11. For Falcon microphone recording support portaudio library is needed.

Of course, you need the GNU C compiler and (GNU) Make, too!

Change to the hatari/ directory, copy Makefile-default.cnf to Makefile.cnf and adapt the configuration file to suite your system. Alternatively, you can use the supplied configure script to auto-detect all parameters (type "./configure --help" to see the options of the script). Don't forget to use some good CFLAGS for the compiler optimizations, e.g. run configure in the following way:

CFLAGS="-O3 -fomit-frame-pointer" ./configure

Then compile Hatari by typing make. If all works fine, you'll get the executable hatari in the src/ subdirectory.

Installation of a TOS ROM

Before you can start Hatari, you have to copy a TOS ROM image to the data directory (the data directory is specified in the configuration file Makefile.cnf) and rename it to tos.img, or use the --tos command line option to tell Hatari where to find a TOS ROM. Hatari needs a TOS ROM image because this contains the operating system of the emulated Atari.

Unfortunately it is not possible to ship an original ROM image with the Hatari package since these images are still copyrighted. But you can easily create an image with a real ST and one of those various ROM-image programs for the ST (search for "TOSDUMP" with your favourite internet search engine). If your old ST does not work anymore, you can also try to search the internet directly for corresponding TOS ROM image, but don't ask the Hatari team where to get one.

Another solution is EmuTOS, which is also shipped with the official release versions of Hatari. EmuTOS is an open-source TOS clone. You can find it at: http://emutos.sourceforge.net/. It is not the best solution for playing games or running other old software due to compatibility issues (see emutos.txt for more details), but it's free and compatible with Hatari.

If you do not specify a TOS image on the commandline nor can Hatari find a suitable TOS image in the default dir, you'll get the chance to select a TOS image file from the GUI.

Installation of the binary

Type make install as root to do a systemwide installation. In this case it is recommended to set the DATADIR variable in Makefile.cnf to a proper value. /usr/local/share/hatari is a good value in that case.

The Hatari executable should now be in your PATH and accessible from anywhere.

When you finally have got a TOS image, try starting Hatari with the option --help to find out more about its command line parameters.

Running Hatari for the first time

Now type hatari to run the emulator for the first time. If all goes well, you should now be presented with a window showing you the familiar little green desktop of the Atari ST. Press F12 to turn on the GUI to configure Hatari to suit your needs, press F11 to toggle windowed and fullscreen mode.

Command line options

Usage:

 hatari [options] [disk image name]

Hatari command line options are split into several categories:

General options

-h, --help
Print command line options and terminate
-v, --version
Print version information and terminate
--confirm-quit <bool>
Whether Hatari confirms quitting
-c, --configfile <filename>
use the given file as configuration file instead of ~/.hatari/hatari.cfg
--fast-forward <bool>
On fast machine helps skipping (fast forwarding) Hatari output

Display options

-m, --mono
Start in monochrome mode instead of color
--monitor <x>
Select monitor type (x = mono/rgb/vga/tv)
-f, --fullscreen
Start the emulator in fullscreen mode
-w, --window
Start the emulator in window mode
--grab
Grab mouse (also) in window mode
-z, --zoom <x>
Zoom low resolution (1=no, 2=yes)
--max-width <x>
Maximum window width for zooming (Falcon/TT only)
--max-height <x>
Maximum window height for zooming (Falcon/TT only)
--aspect <bool>
Whether to do monitor aspect ratio correction (Falcon/TT only)
--borders <bool>
Show ST/STE screen borders (for low/med resolution overscan demos)
--frameskips <x>
Skip <x> frames after each displayed frame to accelerate emulation (0=disabled, >4 uses automatic frameskip with given value as maximum)
--statusbar <bool>
Show statusbar (with floppy leds etc etc)
--drive-led <bool>
Show overlay drive led when statusbar isn’t shown
--spec512 <x>
Hatari uses this threshold to decide when to render a screen with the slower but more accurate Spectrum512 screen conversion functions (0 <= x <= 512, 0=disable)
--bpp <bool>
Force internal bitdepth (x = 8/15/16/32, 0=disable)

VDI options

--vdi <bool>
Whether to use VDI screen mode
--vdi-planes <x>
Use extended VDI resolution with bit depth <x> (x = 1, 2 or 4)
--vdi-width <w>
Use extended VDI resolution with width <w> (320 < w <= 1280)
--vdi-height <h>
Use extended VDI resolution with height <h> (200 < h <= 960)

Video recording options

--avirecord
Start AVI recording
--avi-vcodec <x>
Select avi video codec (x = bmp/png)
--avi-fps <x>
Force avi frame rate (x = 50/60/71/...)
--avi-crop <bool>
Remove status bar from the recorded file
--avi-file <file>
Use <file> to record avi

Devices options

-j, --joystick <port>
Emulate joystick with cursor keys in given port (0-5)
--joy<port> <type>
Set joystick type (none/keys/real) for given port
--printer <file>
Enable printer support and write data to <file>
--midi-in <filename>
Enable MIDI support and write MIDI data to <file>
--midi-out <filename>
Enable MIDI support and read MIDI data from <file>
--rs232-in <filename>
Enable serial port support and use <file> as the input device
--rs232-out <filename>
Enable serial port support and use <file> as the output device

Disk options

--disk-a <file>
Set disk image for floppy drive A
--disk-b <file>
Set disk image for floppy drive B
--protect-floppy <x>
Write protect floppy image contents (on/off/auto). With "auto" option write protection is according to the disk image file attributes.
--protect-hd <x>
Write protect harddrive <dir> contents (on/off/auto). With "auto" option the protection can be controlled by setting individual files attributes as it disables the file attribute modifications for the GEMDOS hard disk emulation.
-d, --harddrive <dir>
Emulate harddrive partition(s) with <dir> contents
--acsi <file>
Emulate an ACSI hard disk with an image <file>
--ide-master <file>
Emulate an IDE master hard disk with an image <file>
--ide-slave <file>
Emulate an IDE slave hard disk with an image <file>
--slowfdc <bool>
slow down FDC emulation (deprecated)

Memory options

-s, --memsize <x>
Set amount of emulated RAM, x = 1 to 14 MiB, or 0 for 512 KiB
-t, --tos <imagefile>
Specify TOS ROM image to use
--cartridge <imagefile>
Use ROM cartridge image <file> (only works if GEMDOS HD emulation and extended VDI resolution are disabled)
--memstate <file>
Load memory snap-shot <file>

CPU options

--cpulevel <x>
Specify CPU (680x0) to use (use x >= 1 with EmuTOS or TOS >= 2.06 only!)
--cpuclock <x>
Set the CPU clock (8, 16 or 32 Mhz)
--compatible <bool>
Use a more compatible but slower 68000 CPU mode

Misc system options

--machine <x>
select machine type (x = st, ste, tt or falcon)
--blitter <bool>
Enable blitter emulation (ST only)
--timer-d <bool>
Patch redundantly high Timer-D frequency set by TOS. This about doubles Hatari speed as the original Timer-D frequency causes most of the interrupts.
--dsp <x>
Falcon DSP emulation (x = none, dummy or emu, Falcon only)
--sound <x>
Sound frequency: 6000-50066. "off" disables the sound and speeds up the emulation. To prevent extra sound artifacts, the frequency should be selected so that it either matches evenly with the STE/TT/Falcon sound DMA (6258, 12517, 250033, 50066 Hz) or your sound card frequencies (11025, 22050, 44100 or 6000...48000 Hz). Check what your sound card supports.
--sound-buffer-size <x>
SDL's sound buffer size : 10-100, or 0 to use default buffer size. By default Hatari uses an SDL buffer size of 1024 samples, which gives approximatively 20-30 ms of sound depending on the chosen sound frequency. Under some OS or with not fully supported sound card, this default setting can cause a bigger delay at lower frequency (nearly 0.5 sec). In that case, you can use this option to force the size of the sound buffer to a fixed number of milliseconds of sound (using 20 is often a good choice if you have such problems). Most users will not need this option.
-k, --keymap <file>
load keyboard mapping from <file>

Debug options

-D, --debug
Toggle whether CPU exceptions invoke the debugger
--bios-intercept
Enable Bios/XBios interception
--trace <trace1,...>
Activate debug traces, see --trace help for available tracing options
--trace-file <file>
Save trace output to <file> (default=stderr)
--parse <file>
Parse/execute debugger commands from <file>
--control-socket <file>
Hatari reads options from given socket at run-time
--log-file <file>
Save log output to <file> (default=stderr)
--log-level <x>
Log output level (x=debug/todo/info/warn/error/fatal)
--alert-level <x>
Show dialog for log messages above given level
--run-vbls <x>
Exit after X VBLs

Type hatari --help to list all the command line options supported by a given version of Hatari.

Using the emulated system

Once you've started Hatari succesfully, you can use the emulator as an almost complete Atari ST computer system.

The GUI

Press F12 to enter the GUI. Navigate it with the mouse. The GUI is rather self explanatory.

The Main Menu

Hatari's GUI - the main menu

You can reach the other setup dialogs from the main menu by clicking on the appropriate buttons.

You can load the current settings from a configuration file by clicking on Load config. and you can save the current settings to a configuration file by clicking on Save config..

Click OK to go back and continue the emulation. All changed options will be applied.

Select the Reset machine option if you want the emulated machine to perform a cold reset. This is equal to switching the power off and on again on a real Atari machine.

Click Quit to terminate Hatari and return to the host OS.

Click Cancel to abandon any changes that you have made.

The File Selector Dialog

Hatari's GUI - the fileselector

The file selector dialog appears whenever you are prompted to choose a file or folder.

To enter a folder or choose a file, simply click on the entry in the main box of the dialog. You can use the arrows at the right, the cursor up and down keys and the page up and down keys to navigate through the list.

You can use the three buttons in the upper right corner for additional folder navigation. Use the .. button to go up one level in the directory tree. Use the ~ button to return to your home directory. The / button can be used to go to the root directory of the file system.

The System Dialog

Hatari's GUI - the system dialog

First you can select the CPU type here. Here are some important hints for choosing the correct CPU type:

Beside the CPU type, you can also choose the machine type to emulate. The ST was the very first 16/32-bit computer from Atari. Most older games and demos require an ST. The STE was introduced some years later and had some more advanced hardware features. There are not that many demos or games that really require an STE but since most normal ST games/demos also work with an STE, it's normally safe to always work in STE mode.
TT and Falcon are more advanced, but they are not as compatible to the ST as the STE was. Therefore many old games and demos do not work with these machine types anymore. There were only very few programs that were made for the TT exclusively, while there were some interesting games and demos specially made for the Falcon. Note: TT and Falcon emulation are incomplete. They may not work very well.

For STE emulation a STE compatible TOS image, e.q. version 1.06, 1.62 or 2.x, is strongly recommended. For TT emulation you need TOS 3.0x and for Falcon emulation you need TOS 4.0x. EmuTOS can be used on all machine types.

Select the CPU clock you want to use. 8Mhz is ST standard and the most compatible. Use 16MHz for Mega STE and Falcon emulation. The CPU in the TT was clocked with 32 MHz.

With the "Slower but more compatible CPU" option, you can enable the emulation of 68k address errors and the CPU prefetch buffer. This is needed for best compatibility, but it slows down emulation a little bit so you can disable it if you don't need it.

For Falcon mode, you can choose whether you want to enable DSP emulation, fake it or completely disable it. Most Falcon programs only play sound or work correctly when you enable the DSP emulation, but it needs a lot of host CPU power (more than 2 GHz). So if you have a slow host CPU, you can try if your Falcon program also runs with DSP disabled or in "dummy" mode. Note that you can not change this option while the DSP based program already runs.

You can also enable/disable Blitter emulation here. The Blitter is a custom chip that accelerates some graphical operations. This switch only toggles the Blitter in plain ST mode. In STE mode, the Blitter is always enabled (since all STEs have been sold with a Blitter chip).

If you enable the "Real time clock emulation" switch, a RTC will be emulated based on the time of the host computer. Note that you need at least TOS 1.02 for proper RTC emulation, TOS 1.00 does not support this.

The Timer-D patch changes the Timer-D initialization from TOS. TOS uses the MFP timer D as a baudrate generator for RS232. However, the TOS default value slows down the emulation. The patch gives you a better performance. It is normally safe to enable the patch, but if you encounter a program that does not work, you can try to disable the patch to see if it works then.

NOTE: The emulated Atari is very very sensitive to these options and it is strongly recommended to reset the emulation after changing them (for most things that's done automatically). The correct CPU type and clock are automatically selected when one uses the --machine command line option.

The Floppy Disks Dialog

Hatari's GUI - the floppy disks dialog

This dialog can be used to choose which floppy disks should be emulated in the disk drives. You can use most standard Atari ST disk image files. You may select and browse also zipped disk images. See the chapter "Floppy disk images" for details.

Click on the button Browse next to the A: and B: option to go to the fileselector to choose a disk image for the corresponding drive.

Click on Eject to eject a disk image from the emulated drive. The emulated ST will act as if had no floppy disk in its drive.

You can specify a default directory where Hatari will start to browse the filesystem.

Check the "Auto insert B" option if you want Hatari to be smart and insert the second disk of a two disk game automatically. Some games then use the second drive automatically. In the case that a game is not able to find the disk in the second drive, you have to insert the second disk in drive A: manually when prompted.
NOTE: This option only works properly if the file name of the first disks ends with an 'a' before the extension and the second disk name ends with a 'b'.

Select if you want to use slow FDC (Floppy Disk Controller) emulation. "Slow floppy access" is normally not required, except for some few slideshows / intros which run too fast without this option.

You can choose if you want Hatari to write-protect your disks. Atari ST virii can spread on disk images too so it might be a good idea to enable the write protection option. However you can't save highscores or games to your disk images in that case.

Hatari's GUI - the new floppy dialog

If you need to create a new blank disk image, click on Create blank image. Parameters for the new image can be set in the following dialog. HD and ED disk sector counts are for non-Atari disk sizes, but such disks are useful for programs that don't work with GEMDOS emulation. Click on Create to save the new image or on Back to return to the disk dialog.

After clicking Create, a fileselector appears. You can browse the filesystem now. Select the target directory, click beside "File:" and type in a name for the new disk image. The name should terminate with .st or .msa.

Hatari can currently create plain .ST and .MSA disk images exclusively. hmsa command line utility can be used to convert disk images between .ST and .MSA formats.

The Hard Disks Dialog

Hatari's GUI - the hard disks dialog

This dialog can be used to change the harddisk settings.

You can select a harddrive image for ACSI, IDE master or slave hard drive emulation via image file here or you may select a directory of your local filesystem to be emulated as the harddrive of the emulated system.

Check "Boot from HD" if you want Hatari to execute the AUTO folder on the harddrive. This option is checked by default if you specify a harddrive image or a directory via the command line.

Removing the check from the "Allow GEMDOS drive modification" option will prevent Atari programs from modifying the files in GEMDOS HDD emulation directory or creating new files under it.

Note that for IDE hard disk emulation you also need a TOS version >= 2.05. And ACSI hard disk emulation does not work with TOS 4.0x in Falcon mode.

The Memory Dialog

Hatari's GUI - the memory dialog

You can select the amount of RAM for the emulated ST here. Only amounts that were valid on a real unmodified STFM can be selected.

Note: This option is critical and you are strongly advised to reset the emulated ST when changing this option.

Here you will find the options to save memory snapshots as well.

Click on Save to save a memory snapshot to file. You can select a new filename here.

Click on Restore to restore a memory snapshot from a file. Use the fileselector to select the snapshot to be restored.

NOTE: Memory snapshots are not interchangeable between different versions of Hatari. E.q. if you compile a newer Hatari, you cannot load your old memory snapshots back.

The ROM Dialog

Hatari's GUI - the ROM dialog

Here you can select the TOS image to use. Click on Browse to select it via the fileselector. You can also select an optional cartridge image to use. Click on Browse to select one via the fileselector. Click on Eject to disconnect the custom cartridge image.

For ST mode, use TOS 1.00, 1.02, 1.04 or 2.06. For STE mode, use TOS 1.06, 1.62, 2.05 or 2.06. If you want to use the TT mode, you must specify a TOS 3.06 image here. And in Falcon mode, you have to use either TOS 4.00, 4.02, 4.04 or 4.92. However, you should always use TOS 4.04 for Falcon mode, it's the most common one. Also note that TOS 4.92 can not be booted from a boot disk (like it's done on a real Falcon), you have to specify it directly in the TOS ROM setup dialog here.

Keep in mind that any custom cartridge image will not work together with GEMDOS hard disk emulation or the VDI extended resolution emulation since some additional driver code will be used in the cartridge memory space for these emulations.

Note: These options are critical and you are strongly advised to reset the emulated ST when changing one of these option.

The Joystick Dialog

Hatari's GUI - the joystick dialog

In this dialog, you can configure the emulated joysticks. With the upper two arrows, you can choose the joystick which you want to configure.

Joystick 1 is the normal ST joystick port and 99.9% of all ST games use this port. Joystick 0 emulates a joystick plugged into the ST mouse port and is often used in games for two players.

With STE joypad A and B, you can enable the emulation of Jaguar joypads which are plugged in the enhanced joystick ports of the Atari STE. Only very few STE games support these joypads, so you often won't need this.

Finally, Hatari also emulates joysticks which were plugged on the parallel port with a special adapter on a real ST. These were used in some few multi-player games like "Gauntlet 2".

For each ST joystick, choose whether you want to disable it, use the keyboard for emulation or use a real PC joystick.

For keyboard emulation, you can select the keys by pressing the Define keys button. You will be prompted to press the keys for up, down, left, right and fire.

If you want to use a real PC joystick for the emulation, you should connect it to your PC before you start Hatari. Then you can choose the joystick with the two lower arrows.

Check the "Enable autofire" option if you are too lazy to pound on the fire button in shoot'em-up games. However, this option only works with certain games. In some other games, it gets worse if you enable this option.

See also the chapter "Emulated Joystick" for details.

The Atari Monitor Dialog

Hatari's
GUI - the Atari monitor dialog

Here you control the video output of the emulated Atari.

You can select which sort of monitor to use. This option depends on the machine type which you have selected in the "System options" dialog. In ST and STE mode, you can choose between monochrome mode (select "Mono") and color mode (select one of the other monitor types). Note that when you select "TV" and use zoomed low resolution or switch to ST medium resolution, you will get a TV-like screen rendering which is a little bit faster but darker compared to the normal "RGB" monitor mode. Switching between mono and a color monitor acts like a monitor switch on a real ST - so beware, this will reboot your emulated system!
In TT mode, you can only choose between TT-high resolution ("Mono") and normal modes (select one of the other monitor types). Finally the Falcon mode supports all four types of monitors. Note that most Falcon demos/games require a RGB or TV mode and do not work with VGA.

"Show ST/STE borders" toggles the displaying of the borders around the ST / STE screen. Some demos and games use the screen borders for displaying additional graphics. As enabling this option increases CPU computing time, don't enable it if you have a very slow computer. This option affects only the ST and STE modes, TT and Falcon modes are always displayed without borders.

Extended VDI resolutions will emulate a sort of extended graphics card in the emulated ST which give you larger resolutions with a higher colordepth for GEM. Select a resolution and color depth. Check to activate. It will disable all other video options mentioned above. Uncheck to get back to a normal ST behaviour.
Note: Using an extended resolution will only work with GEM conformant applications. 99% of all games and demos will not run if you activate any extended resolution here.

The Hatari Screen Dialog

Hatari's
GUI - the Hatari screen dialog

Here you control how the video output of the emulated Atari appears on your screen.

Check "Fullscreen" to run Hatari in fullscreen. By default Hatari runs in windowed mode.

The "Frame Skip" option can be used to speed up the emulator if it is running too slow on your system. Disable frame-skip if you have a fast computer. When selecting 1, 2 or 4, drawing of corresponding number of frames will be skipped after each frame actually shown by Hatari. Select "Auto" to let the emulator to decide whether, and how many frames will be skipped.
Note: The frameskip option also affects the frame rate of the screen animation recording!

"Statusbar" toggles the statusbar at the bottom of the screen. The statusbar shows the floppy drive LEDs, the current frameskip value, the machine type including TOS version and memory size, and whether recording is currently active.

"Max zoomed" option controls up to which size Hatari tries to scale the Atari resolutions and how much of the borders (enabled in Atari Monitor dialog) will be shown. There are several limitations in this:

You should set these values to a size that suits best your monitor resolution. It's intended to help in getting Hatari to best use your monitor space on a windowed mode and in fullscreen avoiding "fuzzy" scaling either by Hatari or your LCD monitor.

Giving "-z 2" option on command line will reset max zoomed size to default values and "-z 1" will disable all zooming. Note that zooming takes additional CPU computing time and should not be enabled on very slow computers.

Click the Screenshot button to create a screenshot in PNG (or BMP) format to the current working directory or click the Record AVI button to record an AVI format video of Hatari screen (and audio) output. You can opt to record new movie frames only when the screen content really changed.

The Keyboard Dialog

Hatari's GUI - the keyboard dialog

Here you can select the keyboard mapping to use. Two different mappings called "Symbolic" and "Scancode" are predefined.

"Symbolic" tries to map the symbolic values of your PC keys to the ST keys. It should be working pretty good on all systems as long as your keyboard layout looks close to the standard english keyboard layout. However, you might experience some problems with special keys like brackets etc.

"Scancode" uses the scancode values of your PC keys for keyboard mapping. This only works on certain architectures like Linux where the scancodes are similar to the ST scancodes (e.g. it does not work on Mac OS X). If it works on your system, this often gives better results than the symbolic mapping. Note that you also need a TOS version with the right language (e.g. use a French TOS if you are using a French keyboard).

You can also load a custom keyboard mapping file here if you wish. Please note that the custom keyboard mapping will use the "symbolic" mapping for all keys that are not defined by your map file. Have a look at the supplied example mapfile (keymap-sample.txt) to see how to create your own keyboard mapping.

When the emulator runs in fast forward mode, and you want to type text, it can be annoying that the emulated system detects multiple key events due to the key repetition of the emulated system. To avoid this you can disable the key repetition in fast forward mode here.

The Sound Dialog

Hatari's GUI - the sound dialog

Here you can control the sound subsystem.

Check if you want emulated sound at all. Emulation is faster if sound emulation is turned off.

Nine frequencies from low to high quality are available. Experiment a little bit to find out which fits best for your setup. For most modern computers, 44100 Hz or 48000 Hz should be fine. For older or slower host systems, you should use a lower frequency. 12517, 250033 and 50066 Hz are frequencies supported by the STE/TT/Falcon sound DMA.

You can select to record a piece of sound here. Use the Browse button to choose a file. The file name extension that you use (.WAV or .YM) determines in which format the sound is recorded in. The Record sound button is a toggle so you will need to return to the GUI to switch sound recording off again (or to use the keyboard shortcut for that).

The Devices Dialog

Hatari's GUI - the device dialog

Check the first checkmark to enable experimental printer support. See the Emulated printer section for details.

As Hatari currently only supports printing to file, click on Browse to select the file to print to. You can enter a new filename as well.

Check the second checkmark to enable experimental RS232 support. The RS232 device is configured according to the settings of the emulated RS232 of the Atari ST. This means Hatari will automatically use baudrate and handshaking as configured for the emulated ST.

Click on Browse to select suitable device files for serial input and output. On Linux a good choice is /dev/ttyS0 or /dev/ttyS1.

Check the third checkmark to enable experimental MIDI support. Click on Browse to select a suitable MIDI device files for MIDI input and output.

midi-linux.txt file explains how to select the correct MIDI device file, how to set up software sound synthetizing on Linux (using Alsa) if your sound card/driver doesn't support MIDI, and how to set up MIDI networking e.g. between multiple Hatari instances.

Keyboard shortcuts

While the emulator is running, you can activate or toggle various features via Hatari keyboard shortcuts. Below are listed the default shortcut key bindings:

Shortcut Purpose
ALTGR+a record animation
ALTGR+g grab a screenshot
ALTGR+i boss key: leave full screen mode, pause Hatari and iconify its window
ALTGR+j toggle joystick emulation via cursor keys on/off between ports 0 and 1
ALTGR+m (un-)lock the mouse into the window
ALTGR+r (warm) reset the ST
ALTGR+c coldreset the ST (same as the original power switch)
ALTGR+d open dialog to select/change disk A
ALTGR+s enable/disable sound
ALTGR+q quit the emulator
ALTGR+x toggle normal speed/fast forward
ALTGR+y enable/disable sound recording
ALTGR+k save memory snapshot
ALTGR+l load memory snapshot
ALTGR+f or F11 toggle between fullscreen and windowed mode
ALTGR+o or F12 activate the options GUI
PAUSE pause emulation
AltGr+PAUSE invoke the internal Hatari debugger

You can change the key bindings from the Hatari configuration file. The required key values can be seen in the SDL_keysym.h include file (usually in /usr/include/SDL/).

Emulated Atari ST keyboard

All other keys on the keyboard act as the normal Atari ST keys so pressing SPACE on your PC will result in an emulated press of the SPACE key on the ST. The following keys have special meanings:

Key Meaning
Alt will act as the ST's ALTERNATE key
left CTRL will act as the ST's CONTROL key
Print Screen will emulate the ST's HELP key
Scroll Lock will emulate the ST's UNDO key
Page Up will emulate the ST's ( key in the keypad
Page Down will emulate the ST's ) in the keypad

If joystick emulation via keyboard is enabled, by default cursor keys are used for the directions and right CTRL key as the fire button. Otherwise they act as corresponding keys of the emulated Atari ST.

NOTE: Problems with simultenous keypresses most likely aren't an issue in Hatari as many modern keyboards report/support only three simultenous key presses (or even just two depending on which keys are in question). Expensive gaming keyboards support more.

Emulated mouse

For obvious reasons your PC mouse will act as the emulated Atari ST mouse. In fullscreen mode it will act as expected, directly controlling the ST mouse pointer.

However it is a little bit different in windowed mode. To make the mouse work there as expected you need to grab it first or lock it into the Hatari window. Do this by pressing the ALTGR+m hotkey combination or starting Hatari with the --grab command line option. Press the shortcut key (again) to go back to normal mouse behaviour which allows you to move mouse outside outside the Hatari window while Hatari is up and running. Note: pausing the emulation will also (temporarily) release the mouse grab.

Mouse scrollwheel will act as cursor up and down keys.

Emulated joystick

The Atari ST joysticks are emulated ofcourse allowing you to play your favourite games with Hatari.

The default mode is to use a connected PC joystick. You can use any joystick that is supported by your kernel. If your joystick works with other applications, it will likely work with Hatari as well. Make sure it is calibrated and then off you go. Move the stick to point into the desired direction. Please note that Hatari will not detect analogue movement as the Atari ST only had digital joysticks. The first firebutton will act as the normal firebutton on the Atari ST while the second firebutton will emulate a keypress of the SPACE key on the ST as many ST games utilize the SPACE bar for secondary game functions. (Xenon for example)

If you do not have a PC joystick or joypad, then you do not need to desperate. You can emulate one of the two Atari ST joysticks via the cursor keys. Just activate it in the GUI. Then the cursor keys will act as the joystick directions, the right CTRL key will act as the firebutton. You can still use the cursor keys as the ST's cursorkeys in this mode as long as you press SHIFT along with the cursorkeys. You can also configure these keys from the joystick options.

Emulated video

Hatari emulates all screen modes of the original machine.

ST/STE shifter overscan effects are emulated, but due to the fact that these effects are achieved by using quirks and glitches in the original chips to do things beyond their specification, emulation is a bit tricky for these effects. As a result, some demos using these techniques might not be displayed correctly in Hatari, known ones are listed in the compatibility.html file.

Beside that you can setup extended VDI modes. These only work with GEM-compliant applications and they are equal to fitting a videocard into your Mega ST.

Make sure to disable extended VDI modes for playing games as 99% of all ST games will not be able to make use of higher resolutions.

Emulated printer

Due to the fact that printer handling is very different between Unix style machines and the Atari ST, emulation of the printer is achieved by writing all printer output to a file.

The file will contain a sequence of data, the same that would appear on the data pins of the Atari ST printer port. That would include control characters and commands for graphic printing. Clicking "Print desktop" on the GEM desktop would result in a messy data dump in the printer output.

Printer emulation works best for plain text files or programs that do not format the output for a specific printer. The file contents can be used with your favourite text editor for further processing and printing to a real printer.

To get real direct printing out of Hatari on a PostScript printer, you may set up a GDOS printer with a PostScript driver on the emulated Atari and set your printer device file as Hatari's printer output.
NOTE: This has not been tested yet and the Hatari team cannot guarantee that it will work.

Emulated RS232

Serial communications in Hatari is designed to directly use a serial port on your PC.

Communications parameters are set automatically upon the settings of the emulated ST. This means all you do is to set the communication parameters like baudrate from your ST communications software. Hatari will do the rest and handle the serial input and output for you.

Floppy disk images

Hatari does not use floppy disks directly but disk images due to differences between the floppy disk controllers of the ST and the PC. Three types of disk images are currently supported: The raw "ST" type, the similar "DIM" type and the compressed "MSA" (Magic-Shadow-Archiver) type.

The raw type (file suffix should be "*.st") is simply a sector by sector image of a real floppy disk. You can easily create such an image with the dd program which should normally be pre-installed on every Unix-like system. Simply type something like dd if=/dev/fd0 of=myimage.st to create a disk image. Of course you need access to /dev/fd0, and depending on your system and the type of floppy disk you might have to use another device name here (for example I use /dev/fd0u720 for 720kB disks). However, if the disk is copy-protected or doesn't use a MSDOS compatible file system, this might fail. So be very careful if you are not sure about the disk format.

The other possibility is to image the disk on a real Atari ST. There are programs like the Magic Shadow Archiver for this task. Hatari supports this slightly compressed MSA disk images, too. Note that Hatari only supports the "old" MSA format, there are some Magic Shadow Archiver clones (like Jay-MSA) that create better compressed but Hatari-incompatible disk images. However, if you have got such a MSA disk and want to use it with Hatari, you can still run the corresponding MSA program within Hatari to extract the incompatible disk image to a normal floppy disk image.

While *.ST and *.MSA are more or less the "standard" types of Atari disk images, you might sometimes also find STT or ADF images on the internet. These currently do not work with Hatari.

Hatari can now also utilize *.DIM images just as *.ST ones without any problems. Note that DIM images are nearly the same as the raw ST images (they only have an additional 32 bytes header), so you can easily transform the DIM images into ST images by stripping the header from the files. For example try something like: dd if=input.dim of=output.st bs=32 skip=1

If you've got a disk image that has been created with the old ST emulator PaCifiST (for DOS) or with early versions of the program Makedisk, and the disk image does not work with Hatari, then the disk probably suffers from the "PaCifiST bootsector bug" (Hatari will display a warning message then). In this case, the bootsector of the disk contains some illegal data, so that the disk even does not work on a real ST any more. However, if it is a .ST and not a .MSA disk, you can easily fix it by using a hex-editor to change the byte at offset $D (13) from 0 to 1 (don't forget to backup your disk image first, since you can also easily destroy your disk image when changing a wrong byte there). If the disk contains a bootsector program, you probably have to adjust the boot sector check sum, too (it can be found at offset $1FE + $1FF).

Hatari supports disk images that are compressed with (Pk-)ZIP (file suffix must be ".zip") or GZip (file suffix must be ".st.gz" or ".msa.gz"), so you can archive your disk images into zip archives. You can also directly run the zip archives you may download from the net as long as the archive contains a disk image in .ST or .MSA format.

Note: Hatari does not save disk images back to *.ZIP files so your highscores and savegames are lost if you load the game from such a zipped disk image.

Hard disk support

Hatari supports three ways of emulating Atari hard drives: The low-level ACSI and IDE hard disk emulation and a GEMDOS based drive emulation. In most cases the GEMDOS based hard disk emulation is best as it allows exchanging files easily between the emulated and the host environment.

Please note that changing the HD-image or the GEMDOS HD-folder will reset the emulated Atari since it is not possible to switch the hard disk while the emulator is running.

On a 32-bit host system, the size of a hard disk image is limited to 2 GB. On 64-bit host systems, bigger images might be possible but the support for bigger images is not tested very well yet.

GEMDOS based hard disk emulation

With the GEMDOS based drive emulation, you can easily "mount" a folder from the host file system to a drive of the emulated Atari. To use the GEMDOS based drive emulation, you should use a folder on your hard disk that only contains files and folders with valid TOS filenames i.e. file and folders names shouldn't contain invalid GEMDOS filename characters and their length shouldn't exceed the 8+3 file name length limit.

If you provide --harddisk option a directory containing only single letter subdirectories, each of these subdirectories will be treated as a separate partition, otherwise the given directory itself will be assigned to drive "C:". In the multiple partition case, the letters used as the subdirectory names will determine to which drives/partitions they're assigned.

GEMDOS drive emulation is an easy way to share files between the host system and the emulated Atari, but there are also some known limitations which are due to the way the GEMDOS drive emulation is implemented:

So, if your programs complain that they could not find/read/write files on the GEMDOS emulated drive, you should try to copy them to a floppy disk image or a real hard disk image!

ACSI hard disk emulation

To use the ACSI hard disk emulation, you need a hard disk image file with a pre-installed HD driver in it. You can try to get an image of your old ST hard disk or grab one from the internet (e.g. from the Hatari website).

To create a new ACSI hard disk image, you can start with an empty image that you have created for example with the following command: dd if=/dev/zero of=hd.img bs=512 count=xxx (where 'xxx' is size in 512 byte blocks). Copy the complete AHDI 5.0 package to a floppy disk image, then boot Hatari with this floppy disk image and the fresh hard disk image like this: --acsi hd.img ahdi.st. Then start HDX.PRG from the floppy disk and format + partition the hard disk image with it.

Formatting and partitioning works currently only with AHDI 5, but you can install the AHDI 6 driver to the hard disk after it's formatted. Restart the emulated system, run AHDI.PRG from the floppy disk to access the hard disk image from the emulated Atari and then run HINSTALL.PRG. After installing the hard disk driver to the fresh HD image with HINSTALL.PRG, you can boot directly from the hard disk image.

IDE hard disk emulation

As the IDE disk format (little endian) differs from the ACSI disk format (big endian), you need separate disk images for them. Hatari doesn't currently support formatting IDE disks with AHDI, but you can do it with Cecile.

First create an empty image file with the size of your choice with: dd if=/dev/zero of=hd.img bs=1k count=xxx. Then get the Cecile hard disk driver from http://centek.free.fr/atari/softs/s_cecile.htm and put it on a floppy disk image (e.g. to one named "cecile.st" using: zip2st.sh cecile.zip).

Run Hatari with hatari --machine falcon --tos tos404.rom --ide-master hd.img cecile.st, switch to larger color resolution and warm up your French language skills. Then start the Cecile hard disk driver CECILE.PRG and run CC_TOOLS.APP to partition your hard disk image. Click the "Partition" button, select "Hatari IDE disk" and set suitable partition size with the arrows (below type field). Then click "Valider".

If you only want to use your HD image in Falcon mode, you can install the Cecile hard disk driver to the image from the Cecile CC_TOOLS.APP: Click the "Installer" button and save the Cecile driver to the 1st partition on "Hatari IDE disk". If you want to also use your HD image in ST/STE mode, you need to get and install AHDI 6 driver on it instead (see ASCI hard disk emulation section).

Then you can boot from your hard disk image by simply specifying it with the --ide-master parameter.

Moving files to/from hard disk images

Moving files to and from Atari hard disk images can be done either through GEMDOS partitions (host directories mounted inside Hatari emulation) or accessing the images directly on the host (outside the emulation). Both have their own limitations.

If it's fine for the IDE/ACSI partitions to be first, you can use hard disk images with AHDI or Cecile driver and a multipartition GEMDOS setup as described in above sections. If you want to boot from a GEMDOS partition i.e. such to be before hard disk image partitions, and still to be able to access all the IDE/ACSI partitions, you need to use HD Driver.

Using HD Driver with GEMDOS partitions

Uwe Seimet's HD Driver works fine with both the Hatari GEMDOS partitions and normal hard disk images. However, it doesn't work with EmuTOS so you need real TOS (at least version v1.04).

First copy the HDDRIVER.PRG binary into your GEMDOS drive emulation directory AUTO folder. Then start the HDDRUTIL.APP configuration utility, locate HDDRIVER.PRG, open the "Devices and Partitions" dialog and select the "Preserve Existing Partitions" option. Then you can just start Hatari with your hard disk image and this GEMDOS directory, for example like this: "hatari --harddisk gemdos-hd/ --ide-master ide-hd.image".

If you're using the demo version of HD Driver, you can write files only to the C: partition, i.e. in above case only copy files from the hard disk image partition to the GEMDOS partition (with some write slowndowns included into the demo version). If you want to copy files to the hard disk image with the demo version of the HD Driver, you need to set the hard disk image as drive C:.

To accomplish this, set the GEMDOS partitions to be from D: forward, i.e. have a directory which contains only single letter subdirectories, starting from "D" like in "mkdir gemdos-hd; mkdir gemdos-hd/D". Then give Hatari (as the last parameter) a boot floppy image containing the demo version of HDDRIVER.PRG in its AUTO folder, like this: "hatari --ide-master ide-hd.image --harddisk gemdos-hd/ hd-driver-floppy.st".

Accessing HDD image partitions outside of Hatari

If you want to access the harddisk image partitions also outside the emulation, the disk image needs to have a DOS partition table. The atari-hd-image script included with Hatari can be used to create such an image.

Inside the Hatari emulator, EmuTOS can access partition(s) on these kind of images directly without any driver software. Of the Atari HD drivers mentioned above, Centek's Cecile and Uwe Seimet's HD Driver (demo) work fine with these partitions. E.g. AHDI and CBHD don't.

Note that plain EmuTOS supports only ACSI and the listed HD drivers support only IDE (emulation). Cecile needs TT or Falcon and HD Driver doesn't work with EmuTOS. To summarise; if ASCI emulation and EmuTOS are enough, use those. Otherwise, if you want to use TT or Falcon emulation, use Cecile (or full HD Driver version if you have it), otherwise use HD Driver (demo).

To access the content of the partitions on Linux host, there are two possibilities:

Using Mtools

For this you need to add an entry for the hard disk image to your ~/.mtoolsrc and specify which partition you want to access from the image. For an image created with the above mentioned script, the line in the configuration file should look something like this:

MTOOLS_NO_VFAT=1
drive c: file="/home/user/hatari/hd.img" partition=1

Note that Mtools is instructed to use FAT compatibility mode because EmuTOS cannot deal properly with VFAT file information. If you don't want this setting for all your Mtools drives, you can set it also via the environment like this ("::" refers to the drive image given with the "-i" option):

MTOOLS_NO_VFAT=1 mcopy -spmv -i hd.img files/* ::

Using a loopback device

This is recommended even by Mtools documentation, but it's less convenient as it requires root rights. First you need to "loop" mount the image:

$ su
# image="hd.img"; mountdir="hd"
# start=$(parted $image unit s print | awk '/ 1 /{print $2}' | tr -d s)
# losetup -f $image -o $((512*$start))
# loop=$(losetup -a | tail -1 | cut -d: -f1)
# mkdir -p $mountdir
# mount -t msdos $loop $mountdir

This uses parted to find out the first partition offset in sectors and then tells losetup to bind the first free loop device to a corresponding offset from the hd.img image. mount is then used to mount the file system from the loop device on top of the "hd" directory.

After you've copied the relevant files to the "hd" directory, you need unmount the file system and remove the loop device binding before using the disk image from Hatari:

# umount $mountdir
# losetup -d $loop

The debugger

Hatari has a built-in debugging interface which can be used for analyzing code that runs in the emulated system. To invoke the debugger, press the AltGr + Pause key combination.

If you start Hatari with the "-D" command line option, m68k exceptions will automatically invoke the debugger. You can toggle this also later from the debugger with the "setopt -D" command.

The debugger uses Hatari's parent console window, so make sure you run Hatari from the command line when you want to use the debugger. On Linux you can add for example an icon to your desktop that runs: xterm -T "Hatari debug window" -e hatari.

General debugger use

At the debugger prompt, type "help" to get a list of all the available commands and their shortcuts:

Generic commands:
           cd (  ) : change directory
     evaluate ( e) : evaluate an expression
         exec (  ) : execute a shell command
         help ( h) : print help
         info ( i) : show machine/OS information
         lock (  ) : lock info to show on entering debugger
      logfile ( f) : open or close log file
        parse ( p) : get debugger commands from file
       setopt ( o) : set Hatari command line and debugger options
    stateload (  ) : restore emulation state
    statesave (  ) : save emulation state
        trace ( t) : select Hatari tracing settings
         quit ( q) : quit emulator

CPU commands:
      address ( a) : set CPU PC address breakpoints
   breakpoint ( b) : set/remove/list conditional CPU breakpoints
       disasm ( d) : disassemble from PC, or given address
       cpureg ( r) : dump register values or set register to value
      memdump ( m) : dump memory
     memwrite ( w) : write bytes to memory
      loadbin ( l) : load a file into memory
      savebin ( s) : save memory to a file
      symbols (  ) : load CPU symbols & their addresses
         cont ( c) : continue emulation / CPU single-stepping

DSP commands:
   dspaddress (da) : set DSP PC address breakpoints
     dspbreak (db) : set/remove/list conditional DSP breakpoints
    dspdisasm (dd) : disassemble DSP code
   dspmemdump (dm) : dump DSP memory
   dspsymbols (  ) : load DSP symbols & their addresses
       dspreg (dr) : read/write DSP registers
      dspcont (dc) : continue emulation / DSP single-stepping

When entering numbers to the debugger commands in other number bases than the default/selected one, they need to be prefixed with a character indicating this. For decimals this prefix is "#" (#15), for hexadecimals "$" ($F), and for binary values it's "%" (%1111). By default the debugger expects all numbers without a prefix to be decimals, but you can change the default number base with the "setopt" command, just give it the desired default number base (bin/dec/hex).

Instead of a number, you can also use an expression, by surrounding it with quotes (""). An expression can contain calculations with register and symbol values in addition to numbers. For example to give a sum of A0 and D0 register values to a command, use "a0+d0".

Note that within expressions parenthesis are used to change the order of precendence, they cannot be used for indicating indirect addressing like with conditional breakpoints (explained below). Even when using expressions within conditional breakpoints. And when using the hexadecimal number base, remember still to prefix with '$' hexadesimal numbers that can be confused with register names (a0-7, d0-7), otherwise results from expressions and conditional breakpoints can be quite surprising.

Expressions are always evaluated before being given to a command. Expressions don't need to be quoted for the "evaluate" or "address" commands as those always interpret their results as expressions.

With command argument completion (see build notes), result from last "evaluate" command can inserted by typing '$' and pressing TAB.

Inspecting emulation state

In the beginning, probably the most interesting commands are "m" and "d" for dumping and disassembling memory regions. You can use "dm" and "dd" commands to do the same for the DSP.

> help memdump
'memdump' or 'm' - dump memory
Usage:  m [start address-[end address]]
        dump memory at address or continue dump from previous address.
> help disasm
'disasm' or 'd' - disassemble from PC, or given address
Usage:  d [start address-[end address]]
        If no address is given, this command disassembles from the last
        position or from current PC if no last position is available.
> disasm
0000aa6e: 2f08 0241 0fff 207c 00fe MOVE.L A0,-(A7)
0000aa70: 0241 0fff 207c 00fe 78c0 AND.W #$0fff,D1
0000aa74: 207c 00fe 78c0 2070 1000 MOVEA.L #$00fe78c0,A0
0000aa7a: 2070 1000 4ed0 0241 0ffe MOVEA.L (A0, D1.W*1, $00) == $00fe34ae,A0
0000aa7e: 4ed0 0241 0ffe 6712 e549 JMP.L (A0)

You can use the "info" command to see state of specific sets of HW registers ("info videl") or Atari OS structures ("info basepage").

By using the "lock" command, you can ask Hatari to show above kind of information whenever you enter the debugger ("lock disasm"). With the "regaddr" subcommand, it can show also disassembly or memory dump of an address pointed by a given register ("lock regaddr disasm a0"). Of the DSP registers, only Rx ones are valid for this subcommand. To disable showing of this extra information, use "lock default".

Debug symbols

You can load symbol name/address information from a file to the debugger with the "symbols" command (and with "dspsymbols" for DSP). These symbolic names can be used in expressions and all breakpoints. They also show up in the "disasm" command output.

The symbols file format is following:

e01034 T random
e01076 T kbdvbase
e0107e T supexec

Where 'T' means text (code), 'D' means data and 'B' BSS section type of address. The symbol hexadecimal address, type letter and name are separated by white space. Empty lines and lines starting with '#' (comments) are ignored.

AHCC C-compiler can provide a symbol file suitable for this with its "-n 'nm' list" option (not enabled by default). If you're reverse engineering some code, you could just create your own symbols file to help in debugging it later.

If you're debugging normal TOS/GEM programs instead of code loaded into fixed address (like EmuTOS), you can use the "info basepage" command to find out the text segment address to which the program code has been loaded into, and then load symbols so that their addresses are offset by the text segment address:

> info basepage
Process basepage information:
- TPA start      : 0x01a1bc
- TPA end +1     : 0x7da700
- Text segment   : 0x01a2bc
- Text size      : 0xe1e0
- Data segment   : 0x02849c
- Data size      : 0x1b76
- BSS segment    : 0x02a012
- BSS size       : 0x3750
- Process DTA    : 0x01a23c
- Parent basepage: 0x00e91c
- Environment    : 0x01a1ae
'PATH='
'C:\'
- Command argslen: 0
> symbols calc.sym 0x01a2bc

Breakpoints

There are two ways to specify breakpoints for Hatari. First, there are the simple address breakpoints which trigger when the CPU (or DSP) program counter hits a given address. Use "a" (or "da" for the DSP) to create them, for example:

> a $e01034
> a some_symbol

(Address breakpoints are just wrappers for conditional breakpoints so you need to use "b" command to remove or list them.)

Then there are the conditional breakpoints which can handle much more complex break conditions; they can track changes to register and memory values with bitmasks, include multiple conditions for triggering a breakpoint and so on. Use "b" (or "db" for the DSP) to manage them. "b help" explains the syntax:

breakpoint = <condition> [ && <condition> ... ] [option]
condition = <value>[.mode] [& <number>] <comparison> <value>[.mode]

where:
        value = [(] <register/symbol/variable name | number> [)]
        number = [#|$|%]<digits>
        comparison = '<' | '>' | '=' | '!'
        addressing mode (width) = 'b' | 'w' | 'l'
        addressing mode (space) = 'p' | 'x' | 'y'
        option = : <count> | 'once' | 'trace'

If the value is in parenthesis like in '($ff820)' or '(a0)', then the used value will be read from the memory address pointed by it. Note that this value is checked at run-time whereas quoted expressions (mentioned above, please read!) are evaluated already when adding a breakpoint. For example, to break when value in adress pointed by A0 matches the value currently in D0, one would use:

> b (a0) = "d0"

M68k addresses can have byte ("b"), word ("w") or long ("l", default) width. DSP addresses belong to different address spaces: "P", "X" or "Y". Note that on DSP only R0-R7 registers can be used for memory addressing.

Examples:

b (r0).x = 1 && (r0).y = 2
b pc = $64543  &&  ($ff820).w & 3 = (a0)  &&  d0 = %1100

The debugger supports also setting conditional breakpoints on values of some internal Hatari variables (listed by "b help"). For example if you want to stop at a specific cycle within a frame (that is, PC relative to the current VBL/HBL in cycles), set breakpoints to specific "HBL" and "LineCycles" variable values. The "e" command can be used to calculate suitable register and variable values.

As a convenience, if the value expressions on both sides of the comparison are exactly the same, right side is replaced with its current value. For inequality ('!') comparison, conditional breakpoint tracks all further changes for the given address/register expression, this can be used for example to find out all value changes in a given memory address (see examples below).

There are also several options that you can use with both breakpoint types. ":trace" option will make breakpoint to print out the tracked value instead of breaking. This can be useful e.g. when tracking changes to some register like in:

> b ($ffff9202).w ! ($ffff9202).w :trace

":once" option that removes breakpoint after hit can be useful when one wants to get out of a loop (when at the instruction that branches back to loop start) or just to get to a specific point in code:

> b pc > pc :once
> a some_symbol :once

Whereas giving count (like ":2") as option will break only on every <count> hit.

After analyzing and/or setting new breakpoints, you can continue the emulation with the "c" command. You can continue for a given number of CPU instructions (or DSP instructions when "dc" is used), or you can continue forever (until a breakpoint triggers) if you omit the instruction count.

Tracing

If you want to continue with real-time disassembling, you can enable it with "trace cpu_disasm" at the debugger prompt before continuing.

Disable tracing with "trace none" when you enter the debugger again. "trace help" (or TAB) can be used to list all the supported trace points.

Because Hatari normally emulates things at the hardware level, tracing Atari OS functions requires setting additional Hatari options which tell it to intercept higher level functionality:

Tracing options can be set even from a program within the emulation if you enable Hatari "--bios-intercept" option and call XBios 255 from the program with a suitable Hatari command line string.

Note that the trace output file can be set only when Hatari starts, it cannot be changed from within the debugger (or emulation).

Build notes

Lastly, the debugger is much nicer to use with the command line history, editing and especially with the command, command argument and symbol name completion support. If you're building Hatari yourself, please make sure that you have the GNU readline development files installed (on Debian / Ubuntu these come from the libreadline5-dev package). Otherwise this doesn't get enabled when you configure Hatari.

ENABLE_TRACING define needs to be set for tracing to work. By default it should be enabled.

Performance

Hatari performance varies between Atari programs, depending on what features Hatari needs to emulate for them. Less accurate Atari emulators may be faster as emulation accuracy has a performance overhead.

Improving Hatari performance

Unless you've disabled compiler optimizations (like GCC's -O2 or -O3 options) in the Hatari build, the extra optimization flags (like GCC's "-mtune=i686") don't seem to have very large effect on Hatari performance. Using GCC -O3 option instead of -O2 can give minor (5-10%) performance improvements for things (demos) that use very heavily interrupts.

However, Hatari can be sped up considerably by giving up some emulation or emulator accuracy. Most of these options should be needed only on slow devices like handhelds.

Emulation options

Emulation options have the largest impact on performance. These options can be changed from the Hatari GUI System dialog and the emulation needs to be rebooted for any of these changes to take an effect!

DSP

Emulating the Falcon DSP is performance-wise several times more demanding than emulating the m68k; DSP runs at higher frequency, executes many instructions for each m68k instruction and emulation isn't as mature and optimized. Unless some program needs DSP, none or dummy DSP emulation mode could be used. Even of the programs that do use DSP, many use it only for background music and work fine without the real DSP emulation.

Timer-D

The single largest factor contributing to general Hatari emulation performance is the handling of interrupts. Enabling Timer-D patching option (about) doubles Hatari ST/STE emulation performance as it significantly reduces the number of interrupts generated by the emulated Atari machine. Using this has adverse effect only for very rare programs.

Compatible CPU

After the DSP and interrupts, m68k emulation takes most time. Disabling the "Slower but more compatible CPU" option will speed up the emulation a lot, but it won't anymore be cycle accurate. This can be fine for many games and other programs, but won't work e.g. for demos using overscan or rasters.

Roughly speaking, for DSP emulation, one needs at least 2Ghz machine. For normal (unpatched) Timer-D frequency on some specific cases (like demos with overscan 512 color animations) one may need over 1GHz machine, but some rare ST/STE demos may require over 1GHz machine even with Timer-D patching. For "Compatible CPU" one needs at least 1/2Ghz machine.

NOTE: Above options may cause some programs not to work correctly. The Hatari Software Compatibility List lists programs known to need real real Falcon DSP emulation or Timer-D frequency. Disabling "Compatible CPU" option is recommended only as a last resort.

Emulator options

Emulator options don't have as large effect on performance as emulation options, but they don't affect the emulated programs at all, just the quality of the emulation "output". These options can also be toggled at run-time without rebooting the emulation.

Sound

Internal Hatari sound handling and the SDL_mixer sound thread libALSA sound processing can account up to 1/3 of the Hatari CPU usage in normal ST/STE emulation. Disabling sound will get rid of that. Using low sound frequency or one matching your sound card may also help. Best is if you disable also background music from the programs you run in Hatari as this can significantly reduce the number of generated interrupts.

Frame skipping

Screen rendering can take noticeable amount of CPU time. The default Hatari "auto" frame skipping should be used unless there's a good reason not to. It will skip converting and showing some of the frames if there's not enough time for them. If your monitor refresh frequency is lower than the selected Hatari monitor frequency (e.g. LCD monitors usually use 60Hz whereas Atari monochrome monitor uses 71Hz), you should use frameskip of one. The reason is that if your SDL library uses VSync to synchronize the output to screen (like OSX one?), with zero frame skip that forces the emulation to run slower than a real Atari. If SDL doesn't use VSync, Hatari does redundant work to convert frames you can't see.

Zooming

If you are not using frame skip, disabling zooming can have noticeable improvement on performance. You can do this by specifying suitably low "Max zoomed" resolution (--zoom 1 command line option sets it to 320x200). If you still want to have a nice fullscreen mode, you should rather add the right resolution mode-lines (e.g. "320x200") to your xorg.conf file. If you still want to use zooming, disabling borders may help a bit.

Spec512 color handling

Handling Spec512 color modes which change the ST/e palette constantly takes some extra CPU. If you have problems with CPU usage in such screens and you care more e.g. from the sound quality than visuals, you can disable the Spec512 mode handling by zeroing the threshold for that with the --spec512 0 option.

Statusbar and drive LED

If your version of libSDL uses VSync to synchronize the screen output, drawing of the statusbar or the drive LED (when statusbar is disabled) may have some minor impact on performance too. Normally they shouldn't.

Btw. Hatari currently runs best in 16 or 32 bits per pixel color depth mode, so try to avoid 24 bits per pixel display modes if possible. 16-bit mode is fastest.

If nothing else helps, try an earlier Hatari version. More accurate emulation or emulator output in newer Hatari versions means that they can be slower despite optimizations.

Measuring the performance

There are a couple of ways to monitor and measure Hatari performance.

By default Hatari has Statusbar visible and automatic frameskip enabled. When Hatari has enough time that it can sleep a little each frame, the statusbar frame skip ("FS") value keeps at zero. If Hatari is completely busy, it will increase to the maximum specified (automatic) frame skip value.

Hatari has also a facility to measure FPS i.e. Frames Per Second. Just enable the --fast-forward option on command line (or use the corresponding keyboard shortcut), and after a while, press the "Pause" key. Whenever Hatari emulation is paused, Hatari will output on console how many VBLs it could show per second along with some other numbers.

It depends on what you want to measure, but usually it's best to disable sound and set high frame skip like --sound off --frameskips 60 so that the associated external overheads are minimized. E.g. video output can on some platforms do VSync and measurements would then show your monitor refresh frequency instead of actual Hatari performance.

On Unix systems with times() function call, only the time spent by the Hatari process itself is measured. On other systems much less accurate SDL "wall clock" timings are used. To make latter more accurate you could use also --run-vbls option to specify how many VBLs Hatari should run before it exits. In this case it's best to either have the test-case run automatically from the AUTO-folder or given as memory snapshot to Hatari with the frame skip set equal to the VBL count.

Note that the numbers can fluctuate quite a bit, especially when the SDL timings are used, so for (statistically) reliable numbers you may need to repeat the measurement several times. You should of course make also sure that the system doesn't have any other activity at the same time you're making the measurements.

Appendix

Copying

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA

The GNU Project and the Free Software Foundation | The GNU General Public License

Introduction to Emulation

Emulation via software is an art and Hatari is an example of this.

Emulation is to make a computer behave like a (probably) completely different machine on the lowest possible niveau. This includes CPU and custom chip emulation allowing software written for the emulated machine to be run without notice. A good emulator will run most of the software intended for the emulated platform without trouble.

The key to emulation is to simply do those things with a software program, the emulator, that normally chips would perform. So you have an CPU emulator that basically consists of a large loop that does exactly what the real thing would do:

The typical von-Neumann CPU can be emulated very fast, stable and error-free using such a simple loop system.

But in most cases the CPU emulation is the simplest part. Correct emulation of the various custom chips and hardware parts of the emulated system is much trickier.



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