MAME Lua Class Reference

Introduction

Various aspects of MAME can be controlled using Lua scripting. Many key classes are exposed as Lua objects.

Containers

Many properties yield container wrappers. Container wrappers are cheap to create, and provide an interface that is similar to a read-only table. The complexity of operations may vary. Container wrappers usually provide most of these operations:

#c

Get the number of items in the container.

c[k]

Returns the item corresponding to the key k, or nil if the key is not present.

pairs(c)

Iterate container by key and value. The key is what you would pass to the index operator or the get method to get the value.

ipairs(c)

Iterate container by index and value. The index is what you would pass to the at method to get the value (this may be the same as the key for some containers).

c:empty()

Returns a Boolean indicating whether there are no items in the container.

c:get(k)

Returns the item corresponding to the key k, or nil if the key is not present. Usually equivalent to the index operator.

c:at(i)

Returns the value at the 1-based index i, or nil if it is out of range.

c:find(v)

Returns the key for item v, or nil if it is not in the container. The key is what you would pass to the index operator to get the value.

c:index_of(v)

Returns the 1-based index for item v, or nil if it is not in the container. The index is what you would pass to the at method to get the value.

Core classes

Many of MAME’s core classes used to implement an emulation session are available to Lua scripts.

MAME machine manager

Wraps MAME’s mame_machine_manager class, which holds the running machine, UI manager, and other global components.

Instantiation

manager

The MAME machine manager is available as a global variable in the Lua environment.

Properties

manager.machine (read-only)

The running machine for the current emulation session.

manager.ui (read-only)

The UI manager for the current session.

manager.options (read-only)

The emulation options for the current session.

manager.plugins[] (read-only)

Gets information about the Lua plugins that are present, indexed by name. The index get, at and index_of methods have O(n) complexity.

Running machine

Wraps MAME’s running_machine class, which represents an emulation session. It provides access to the other core objects that implement an emulation session as well as the emulated device tree.

Instantiation

manager.machine

Gets the running machine instance for the current emulation session.

Methods

machine:exit()

Schedules an exit from the current emulation session. This will either return to the system selection menu or exit the application, depending on how it was started. This method returns immediately, before the scheduled exit takes place.

machine:hard_reset()

Schedules a hard reset. This is implemented by tearing down the emulation session and starting another emulation session for the same system. This method returns immediately, before the scheduled reset takes place.

machine:soft_reset()

Schedules a soft reset. This is implemented by calling the reset method of the root device, which is propagated down the device tree. This method returns immediately, before the scheduled reset takes place.

machine:save(filename)

Schedules saving machine state to the specified file. If the file name is a relative path, it is considered to be relative to the first configured save state directory. This method returns immediately, before the machine state is saved. If this method is called when a save or load operation is already pending, the previously pending operation will be cancelled.

machine:load(filename)

Schedules loading machine state from the specified file. If the file name is a relative path, the configured save state directories will be searched. This method returns immediately, before the machine state is saved. If this method is called when a save or load operation is already pending, the previously pending operation will be cancelled.

machine:popmessage([msg])

Displays a pop-up message to the user. If the message is not provided, the currently displayed pop-up message (if any) will be hidden.

machine:logerror(msg)

Writes the message to the machine error log. This may be displayed in a debugger window, written to a file, or written to the standard error output.

Properties

machine.system (read-only)

The driver metadata for the current system.

machine.parameters (read-only)

The parameters manager for the current emulation session.

machine.video (read-only)

The video manager for the current emulation session.

machine.sound (read-only)

The sound manager for the current emulation session.

machine.output (read-only)

The output manager for the current emulation session.

machine.memory (read-only)

The emulated memory manager for the current emulation session.

machine.ioport (read-only)

The I/O port manager for the current emulation session.

machine.input (read-only)

The input manager for the current emulation session.

machine.natkeyboard (read-only)

Gets the natural keyboard manager, used for controlling keyboard and keypad input to the emulated system.

machine.uiinput (read-only)

The UI input manager for the current emulation session.

machine.render (read-only)

The render manager for the current emulation session.

machine.debugger (read-only)

The debugger manager for the current emulation session, or nil if the debugger is not enabled.

machine.options (read-only)

The user-specified options for the current emulation session.

machine.samplerate (read-only)

The output audio sample rate in Hertz.

machine.paused (read-only)

A Boolean indicating whether emulation is not currently running, usually because the session has been paused or the emulated system has not completed starting.

machine.exit_pending (read-only)

A Boolean indicating whether the emulation session is scheduled to exit.

machine.hard_reset_pending (read-only)

A Boolean indicating whether a hard reset of the emulated system is pending.

machine.devices (read-only)

A device enumerator that yields all devices in the emulated system.

machine.screens (read-only)

A device enumerator that yields all screen devices in the emulated system.

machine.cassettes (read-only)

A device enumerator that yields all cassette image devices in the emulated system.

machine.images (read-only)

A device enumerator that yields all media image devices in the emulated system.

machine.slots (read-only)

A device enumerator that yields all slot devices in the emulated system.

Video manager

Wraps MAME’s video_manager class, which is responsible for coordinating emulated video drawing, speed throttling, and reading host inputs.

Instantiation

manager.machine.video

Gets the video manager for the current emulation session.

Methods

video:frame_update()

Updates emulated screens, reads host inputs, and updates video output.

video:snapshot()

Saves snapshot files according to the current configuration. If MAME is configured to take native emulated screen snapshots, one snapshot will be saved for each emulated screen that is visible in a host window/screen with the current view configuration. If MAME is not configured to use take native emulated screen snapshots or if the system has no emulated screens, a single snapshot will be saved using the currently selected snapshot view.

video:begin_recording([filename], [format])

Stops any video recordings currently in progress and starts recording either the visible emulated screens or the current snapshot view, depending on whether MAME is configured to take native emulated screen snapshots.

If the file name is not supplied, the configured snapshot file name is used. If the file name is a relative path, it is interpreted relative to the first configured snapshot directory. If the format is supplied, it must be "avi" or "mng". If the format is not supplied, it defaults to AVI.

video:end_recording()

Stops any video recordings that are in progress.

video:snapshot_size()

Returns the width and height in pixels of snapshots created with the current snapshot target configuration and emulated screen state. This may be configured explicitly by the user, or calculated based on the selected snapshot view and the resolution of any visible emulated screens.

video:snapshot_pixels()

Returns the pixels of a snapshot created using the current snapshot target configuration as 32-bit integers packed into a binary string in host Endian order. Pixels are organised in row-major order, from left to right then top to bottom. Pixel values are colours in RGB format packed into 32-bit integers.

Properties

video.speed_factor (read-only)

Configured emulation speed adjustment in per mille (i.e. the ratio to normal speed multiplied by 1,000).

video.throttled (read/write)

A Boolean indicating whether MAME should wait before video updates to avoid running faster than the target speed.

video.throttle_rate (read/write)

The target emulation speed as a ratio of full speed adjusted by the speed factor (i.e. 1 is normal speed adjusted by the speed factor, larger numbers are faster, and smaller numbers are slower).

video.frameskip (read/write)

The number of emulated video frames to skip drawing out of every twelve, or -1 to automatically adjust the number of frames to skip to maintain the target emulation speed.

video.speed_percent (read-only)

The current emulated speed as a percentage of the full speed adjusted by the speed factor.

video.effective_frameskip (read-only)

The number of emulated frames that are skipped out of every twelve.

video.skip_this_frame (read-only)

A Boolean indicating whether the video manager will skip drawing emulated screens for the current frame.

video.snap_native (read-only)

A Boolean indicating whether the video manager will take native emulated screen snapshots. In addition to the relevant configuration setting, the emulated system must have at least one emulated screen.

video.is_recording (read-only)

A Boolean indicating whether any video recordings are currently in progress.

video.snapshot_target (read-only)

The render target used to produce snapshots and video recordings.

Sound manager

Wraps MAME’s sound_manager class, which manages the emulated sound stream graph and coordinates sound output.

Instantiation

manager.machine.sound

Gets the sound manager for the current emulation session.

Methods

sound:start_recording([filename])

Starts recording to a WAV file. Has no effect if currently recording. If the file name is not supplied, uses the configured WAV file name (from command line or INI file), or has no effect if no WAV file name is configured. Returns true if recording started, or false if recording is already in progress, opening the output file failed, or no file name was supplied or configured.

sound:stop_recording()

Stops recording and closes the file if currently recording to a WAV file.

sound:get_samples()

Returns the current contents of the output sample buffer as a binary string. Samples are 16-bit integers in host byte order. Samples for left and right stereo channels are interleaved.

Properties

sound.muted (read-only)

A Boolean indicating whether sound output is muted for any reason.

sound.ui_mute (read/write)

A Boolean indicating whether sound output is muted at the request of the user.

sound.debugger_mute (read/write)

A Boolean indicating whether sound output is muted at the request of the debugger.

sound.system_mute (read/write)

A Boolean indicating whether sound output is muted at the request of the emulated system.

sound.attenuation (read/write)

The output volume attenuation in decibels. Should generally be a negative integer or zero.

sound.recording (read-only)

A Boolean indicating whether sound output is currently being recorded to a WAV file.

Output manager

Wraps MAME’s output_manager class, providing access to system outputs that can be used for interactive artwork or consumed by external programs.

Instantiation

manager.machine.output

Gets the output manager for the current emulation session.

Methods

output:set_value(name, val)

Sets the specified output value. The value must be an integer. The output will be created if it does not already exist.

output:set_indexed_value(prefix, index, val)

Appends the index (formatted as a decimal integer) to the prefix and sets the value of the corresponding output. The value must be an integer. The output will be created if it does not already exist.

output:get_value(name)

Returns the value of the specified output, or zero if it doesn’t exist.

output:get_indexed_value(prefix, index)

Appends the index (formatted as a decimal integer) to the prefix and returns the value of the corresponding output, or zero if it doesn’t exist.

output:name_to_id(name)

Gets the per-session unique integer ID for the specified output, or zero if it doesn’t exist.

output:id_to_name(id)

Gets the name for the output with the specified per-session unique ID, or nil if it doesn’t exist. This method has O(n) complexity, so avoid calling it when performance is important.

Parameters manager

Wraps MAME’s parameters_manager class, which provides a simple key-value store for metadata from system ROM definitions.

Instantiation

manager.machine.parameters

Gets the parameters manager for the current emulation session.

Methods

parameters:lookup(tag)

Gets the value for the specified parameter if it is set, or an empty string if it is not set.

parameters:add(tag, value)

Sets the specified parameter if it is not set. Has no effect if the specified parameter is already set.

UI manager

Wraps MAME’s mame_ui_manager class, which handles menus and other user interface functionality.

Instantiation

manager.ui

Gets the UI manager for the current session.

Methods

ui:get_char_width(ch)

Gets the width of a Unicode character as a proportion of the width of the UI container in the current font at the configured UI line height.

ui:get_string_width(str)

Gets the width of a string as a proportion of the width of the UI container in the current font at the configured UI line height.

ui:set_aggressive_input_focus(enable)

On some platforms, this controls whether MAME should accept input focus in more situations than when its windows have UI focus.

Properties

ui.options (read-only)

The UI options for the current session.

ui.line_height (read-only)

The configured UI text line height as a proportion of the height of the UI container.

ui.menu_active (read-only)

A Boolean indicating whether an interactive UI element is currently active. Examples include menus and slider controls.

ui.single_step (read/write)

A Boolean controlling whether the emulated system should be automatically paused when the next frame is drawn. This property is automatically reset when the automatic pause happens.

ui.show_fps (read/write)

A Boolean controlling whether the current emulation speed and frame skipping settings should be displayed.

ui.show_profiler (read/write)

A Boolean controlling whether profiling statistics should be displayed.

System driver metadata

Provides some metadata for an emulated system.

Instantiation

emu.driver_find(name)

Gets the driver metadata for the system with the specified short name, or nil if no such system exists.

manager.machine.system

Gets the driver metadata for the current system.

Properties

driver.name (read-only)

The short name of the system, as used on the command line, in configuration files, and when searching for resources.

driver.description (read-only)

The full display name for the system.

driver.year (read-only)

The release year for the system. May contain question marks if not known definitively.

driver.manufacturer (read-only)

The manufacturer, developer or distributor of the system.

driver.parent (read-only)

The short name of parent system for organisation purposes, or "0" if the system has no parent.

driver.compatible_with (read-only)

The short name of a system that this system is compatible with software for, or nil if the system is not listed as compatible with another system.

driver.source_file (read-only)

The source file where this system driver is defined. The path format depends on the toolchain the emulator was built with.

driver.rotation (read-only)

A string indicating the rotation applied to all screens in the system after the screen orientation specified in the machine configuration is applied. Will be one of "rot0", "rot90", "rot180" or "rot270".

driver.type (read-only)

A string providing a system type. Will be one of "arcade", "console", "computer" or "other". This is for informational purposes only, and may not be supported in the future.

driver.not_working (read-only)

A Boolean indicating whether the system is marked as not working.

driver.supports_save (read-only)

A Boolean indicating whether the system supports save states.

driver.no_cocktail (read-only)

A Boolean indicating whether screen flipping in cocktail mode is unsupported.

driver.is_bios_root (read-only)

A Boolean indicating whether this system represents a system that runs software from removable media without media present.

driver.requires_artwork (read-only)

A Boolean indicating whether the system requires external artwork to be usable.

driver.clickable_artwork (read-only)

A Boolean indicating whether the system requires clickable artwork features to be usable.

driver.unofficial (read-only)

A Boolean indicating whether this is an unofficial but common user modification to a system.

driver.no_sound_hw (read-only)

A Boolean indicating whether the system has no sound output hardware.

driver.mechanical (read-only)

A Boolean indicating whether the system depends on mechanical features that cannot be properly simulated.

driver.is_incomplete (read-only)

A Boolean indicating whether the system is a prototype with incomplete functionality.

Lua plugin

Provides a description of an available Lua plugin.

Instantiation

manager.plugins[name]

Gets the description of the Lua plugin with the specified name, or nil if no such plugin is available

Properties

plugin.name (read-only)

The short name of the plugin, used in configuration and when accessing the plugin programmatically.

plugin.description (read-only)

The display name for the plugin.

plugin.type (read-only)

The plugin type. May be "plugin" for user-loadable plugins, or "library" for libraries providing common functionality to multiple plugins.

plugin.directory (read-only)

The path to the directory containing the plugin’s files.

plugin.start (read-only)

A Boolean indicating whether the plugin enabled.

Devices

Several device classes and device mix-ins classes are exposed to Lua. Devices can be looked up by tag or enumerated.

Device enumerators

Device enumerators are special containers that allow iterating over devices and looking up devices by tag. A device enumerator can be created to find any kind of device, to find devices of a particular type, or to find devices that implement a particular interface. When iterating using pairs or ipairs, devices are returned by walking the device tree depth-first in creation order.

The index get operator looks up a device by tag. It returns nil if no device with the specified tag is found, or if the device with the specified tag does not meet the type/interface requirements of the device enumerator. The complexity is O(1) if the result is cached, but an uncached device lookup is expensive. The at method has O(n) complexity.

If you create a device enumerator with a starting point other than the root machine device, passing an absolute tag or a tag containing parent references to the index operator may return a device that would not be discovered by iteration. If you create a device enumerator with restricted depth, devices that would not be found due to being too deep in the hierarchy can still be looked up by tag.

Creating a device enumerator with depth restricted to zero can be used to downcast a device or test whether a device implements a certain interface. For example this will test whether a device implements the media image interface:

image_intf = emu.image_enumerator(device, 0):at(1)
if image_intf then
    print(string.format("Device %s mounts images", device.tag))
end

Instantiation

manager.machine.devices

Returns a device enumerator that will iterate over devices in the system.

manager.machine.screens

Returns a device enumerator that will iterate over screen devices in the system.

manager.machine.cassettes

Returns a device enumerator that will iterate over cassette image devices in the system.

manager.machine.images

Returns a device enumerator that will iterate over media image devices in the system.

manager.machine.slots

Returns a device enumerator that will iterate over slot devices in the system.

emu.device_enumerator(device, [depth])

Returns a device enumerator that will iterate over devices in the sub-tree starting at the specified device. The specified device will be included. If the depth is provided, it must be an integer specifying the maximum number of levels to iterate below the specified device (i.e. 1 will limit iteration to the device and its immediate children).

emu.screen_enumerator(device, [depth])

Returns a device enumerator that will iterate over screen devices in the sub-tree starting at the specified device. The specified device will be included if it is a screen device. If the depth is provided, it must be an integer specifying the maximum number of levels to iterate below the specified device (i.e. 1 will limit iteration to the device and its immediate children).

emu.cassette_enumerator(device, [depth])

Returns a device enumerator that will iterate over cassette image devices in the sub-tree starting at the specified device. The specified device will be included if it is a cassette image device. If the depth is provided, it must be an integer specifying the maximum number of levels to iterate below the specified device (i.e. 1 will limit iteration to the device and its immediate children).

emu.image_enumerator(device, [depth])

Returns a device enumerator that will iterate over media image devices in the sub-tree starting at the specified device. The specified device will be included if it is a media image device. If the depth is provided, it must be an integer specifying the maximum number of levels to iterate below the specified device (i.e. 1 will limit iteration to the device and its immediate children).

emu.slot_enumerator(device, [depth])

Returns a device enumerator that will iterate over slot devices in the sub-tree starting at the specified device. The specified device will be included if it is a slot device. If the depth is provided, it must be an integer specifying the maximum number of levels to iterate below the specified device (i.e. 1 will limit iteration to the device and its immediate children).

Device

Wraps MAME’s device_t class, which is a base of all device classes.

Instantiation

manager.machine.devices[tag]

Gets a device by tag relative to the root machine device, or nil if no such device exists.

manager.machine.devices[tag]:subdevice(tag)

Gets a device by tag relative to another arbitrary device, or nil if no such device exists.

Methods

device:subtag(tag)

Converts a tag relative to the device to an absolute tag.

device:siblingtag(tag)

Converts a tag relative to the device’s parent device to an absolute tag.

device:memshare(tag)

Gets a memory share by tag relative to the device, or nil if no such memory share exists.

device:membank(tag)

Gets a memory bank by tag relative to the device, or nil if no such memory bank exists.

device:memregion(tag)

Gets a memory region by tag relative to the device, or nil if no such memory region exists.

device:ioport(tag)

Gets an I/O port by tag relative to the device, or nil if no such I/O port exists.

device:subdevice(tag)

Gets a device by tag relative to the device.

device:siblingdevice(tag)

Gets a device by tag relative to the device’s parent.

device:parameter(tag)

Gets a parameter value by tag relative to the device, or an empty string if the parameter is not set.

Properties

device.tag (read-only)

The device’s absolute tag in canonical form.

device.basetag (read-only)

The last component of the device’s tag (i.e. its tag relative to its immediate parent), or "root" for the root machine device.

device.name (read-only)

The full display name for the device’s type.

device.shortname (read-only)

The short name of the devices type (this is used, e.g. on the command line, when looking for resource like ROMs or artwork, and in various data files).

device.owner (read-only)

The device’s immediate parent in the device tree, or nil for the root machine device.

device.configured (read-only)

A Boolean indicating whether the device has completed configuration.

device.started (read-only)

A Boolean indicating whether the device has completed starting.

device.debug (read-only)

The debugger interface to the device if it is a CPU device, or nil if it is not a CPU device or the debugger is not enabled.

device.spaces[] (read-only)

A table of the device’s address spaces, indexed by name. Only valid for devices that implement the memory interface. Note that the names are specific to the device type and have no special significance.

Screen device

Wraps MAME’s screen_device class, which represents an emulated video output.

Instantiation

manager.machine.screens[tag]

Gets a screen device by tag relative to the root machine device, or nil if no such device exists or it is not a screen device.

Base classes

Methods

screen:orientation()

Returns the rotation angle in degrees (will be one of 0, 90, 180 or 270), whether the screen is flipped left-to-right, and whether the screen is flipped top-to-bottom. This is the final screen orientation after the screen orientation specified in the machine configuration and the rotation for the system driver are applied.

screen:time_until_pos(v, [h])

Gets the time remaining until the raster reaches the specified position. If the horizontal component of the position is not specified, it defaults to zero (0, i.e. the beginning of the line). The result is a floating-point number in units of seconds.

screen:time_until_vblank_start()

Gets the time remaining until the start of the vertical blanking interval. The result is a floating-point number in units of seconds.

screen:time_until_vblank_end()

Gets the time remaining until the end of the vertical blanking interval. The result is a floating-point number in units of seconds.

screen:snapshot([filename])

Saves a screen snapshot in PNG format. If no filename is supplied, the configured snapshot path and name format will be used. If the supplied filename is not an absolute path, it is interpreted relative to the first configured snapshot path. The filename may contain conversion specifiers that will be replaced by the system name or an incrementing number.

Returns a file error if opening the snapshot file failed, or nil otherwise.

screen:pixel(x, y)

Gets the pixel at the specified location. Coordinates are in pixels, with the origin at the top left corner of the visible area, increasing to the right and down. Returns either a palette index or a colour in RGB format packed into a 32-bit integer. Returns zero (0) if the specified point is outside the visible area.

screen:pixels()

Returns all visible pixels as 32-bit integers packed into a binary string in host Endian order. Pixels are organised in row-major order, from left to right then top to bottom. Pixels values are either palette indices or colours in RGB format packed into 32-bit integers.

screen:draw_box(left, top, right, bottom, [line], [fill])

Draws an outlined rectangle with edges at the specified positions.

Coordinates are floating-point numbers in units of screen pixels, with the origin at (0, 0). Note that screen pixels often aren’t square. The coordinate system is rotated if the screen is rotated, which is usually the case for vertical-format screens. Before rotation, the origin is at the top left, and coordinates increase to the right and downwards. Coordinates are limited to the screen area.

The fill and line colours are in alpha/red/green/blue (ARGB) format. Channel values are in the range 0 (transparent or off) to 255 (opaque or full intensity), inclusive. Colour channel values are not pre-multiplied by the alpha value. The channel values must be packed into the bytes of a 32-bit unsigned integer, in the order alpha, red, green, blue from most-significant to least-significant byte. If the line colour is not provided, the UI text colour is used; if the fill colour is not provided, the UI background colour is used.

screen:draw_line(x1, y1, x2, y2, bottom, [color])

Draws a line from (x1, y1) to (x2, y2).

Coordinates are floating-point numbers in units of screen pixels, with the origin at (0, 0). Note that screen pixels often aren’t square. The coordinate system is rotated if the screen is rotated, which is usually the case for vertical-format screens. Before rotation, the origin is at the top left, and coordinates increase to the right and downwards. Coordinates are limited to the screen area.

The line colour is in alpha/red/green/blue (ARGB) format. Channel values are in the range 0 (transparent or off) to 255 (opaque or full intensity), inclusive. Colour channel values are not pre-multiplied by the alpha value. The channel values must be packed into the bytes of a 32-bit unsigned integer, in the order alpha, red, green, blue from most-significant to least-significant byte. If the line colour is not provided, the UI text colour is used.

screen:draw_text(x|justify, y, text, [foreground], [background])

Draws text at the specified position. If the screen is rotated the text will be rotated.

If the first argument is a number, the text will be left-aligned at this X coordinate. If the first argument is a string, it must be "left", "center" or "right" to draw the text left-aligned at the left edge of the screen, horizontally centred on the screen, or right-aligned at the right edge of the screen, respectively. The second argument specifies the Y coordinate of the maximum ascent of the text.

Coordinates are floating-point numbers in units of screen pixels, with the origin at (0, 0). Note that screen pixels often aren’t square. The coordinate system is rotated if the screen is rotated, which is usually the case for vertical-format screens. Before rotation, the origin is at the top left, and coordinates increase to the right and downwards. Coordinates are limited to the screen area.

The foreground and background colours is in alpha/red/green/blue (ARGB) format. Channel values are in the range 0 (transparent or off) to 255 (opaque or full intensity), inclusive. Colour channel values are not pre-multiplied by the alpha value. The channel values must be packed into the bytes of a 32-bit unsigned integer, in the order alpha, red, green, blue from most-significant to least-significant byte. If the foreground colour is not provided, the UI text colour is used; if the background colour is not provided, the UI background colour is used.

Properties

screen.width (read-only)

The width of the bitmap produced by the emulated screen in pixels.

screen.height (read-only)

The height of the bitmap produced by the emulated screen in pixels.

screen.refresh (read-only)

The screen’s configured refresh rate in Hertz (this may not reflect the current value).

screen.refresh_attoseconds (read-only)

The screen’s configured refresh interval in attoseconds (this may not reflect the current value).

screen.xoffset (read-only)

The screen’s default X position offset. This is a floating-point number where one (1) corresponds to the X size of the screen’s container. This may be useful for restoring the default after adjusting the X offset via the screen’s container.

screen.yoffset (read-only)

The screen’s default Y position offset. This is a floating-point number where one (1) corresponds to the Y size of the screen’s container. This may be useful for restoring the default after adjusting the Y offset via the screen’s container.

screen.xscale (read-only)

The screen’s default X scale factor, as a floating-point number. This may be useful for restoring the default after adjusting the X scale via the screen’s container.

screen.yscale (read-only)

The screen’s default Y scale factor, as a floating-point number. This may be useful for restoring the default after adjusting the Y scale via the screen’s container.

screen.pixel_period (read-only)

The interval taken to draw a horizontal pixel, as a floating-point number in units of seconds.

screen.scan_period (read-only)

The interval taken to draw a scan line (including the horizontal blanking interval), as a floating-point number in units of seconds.

screen.frame_period (read-only)

The interval taken to draw a complete frame (including blanking intervals), as a floating-point number in units of seconds.

screen.frame_number (read-only)

The current frame number for the screen. This increments monotonically each frame interval.

screen.container (read-only)

The render container used to draw the screen.

Cassette image device

Wraps MAME’s cassette_image_device class, representing a compact cassette mechanism typically used by a home computer for program storage.

Instantiation

manager.machine.cassettes[tag]

Gets a cassette image device by tag relative to the root machine device, or nil if no such device exists or it is not a cassette image device.

Methods

cassette:stop()

Disables playback.

cassette:play()

Enables playback. The cassette will play if the motor is enabled.

cassette:forward()

Sets forward play direction.

cassette:reverse()

Sets reverse play direction.

cassette:seek(time, whence)

Jump to the specified position on the tape. The time is a floating-point number in units of seconds, relative to the point specified by the whence argument. The whence argument must be one of "set", "cur" or "end" to seek relative to the start of the tape, the current position, or the end of the tape, respectively.

Properties

cassette.is_stopped (read-only)

A Boolean indicating whether the cassette is stopped (i.e. not recording and not playing).

cassette.is_playing (read-only)

A Boolean indicating whether playback is enabled (i.e. the cassette will play if the motor is enabled).

cassette.is_recording (read-only)

A Boolean indicating whether recording is enabled (i.e. the cassette will record if the motor is enabled).

cassette.motor_state (read/write)

A Boolean indicating whether the cassette motor is enabled.

cassette.speaker_state (read/write)

A Boolean indicating whether the cassette speaker is enabled.

cassette.position (read-only)

The current position as a floating-point number in units of seconds relative to the start of the tape.

cassette.length (read-only)

The length of the tape as a floating-point number in units of seconds, or zero (0) if no tape image is mounted.

Image device interface

Wraps MAME’s device_image_interface class which is a mix-in implemented by devices that can load media image files.

Instantiation

manager.machine.images[tag]

Gets an image device by tag relative to the root machine device, or nil if no such device exists or it is not a media image device.

Methods

image:load(filename)

Loads the specified file as a media image. Returns "pass" or "fail".

image:load_software(name)

Loads a media image described in a software list. Returns "pass" or "fail".

image:unload()

Unloads the mounted image.

image:create(filename)

Creates and mounts a media image file with the specified name. Returns "pass" or "fail".

image:display()

Returns a “front panel display” string for the device, if supported. This can be used to show status information, like the current head position or motor state.

Properties

image.is_readable (read-only)

A Boolean indicating whether the device supports reading.

image.is_writeable (read-only)

A Boolean indicating whether the device supports writing.

image.must_be_loaded (read-only)

A Boolean indicating whether the device requires a media image to be loaded in order to start.

image.is_reset_on_load (read-only)

A Boolean indicating whether the device requires a hard reset to change media images (usually for cartridge slots that contain hardware in addition to memory chips).

image.image_type_name (read-only)

A string for categorising the media device.

image.instance_name (read-only)

The instance name of the device in the current configuration. This is used for setting the media image to load on the command line or in INI files. This is not stable, it may have a number appended that may change depending on slot configuration.

image.brief_instance_name (read-only)

The brief instance name of the device in the current configuration. This is used for setting the media image to load on the command line or in INI files. This is not stable, it may have a number appended that may change depending on slot configuration.

image.formatlist[] (read-only)

The media image formats supported by the device, indexed by name. The index operator and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

image.exists (read-only)

A Boolean indicating whether a media image file is mounted.

image.readonly (read-only)

A Boolean indicating whether a media image file is mounted in read-only mode.

image.filename (read-only)

The full path to the mounted media image file, or nil if no media image is mounted.

image.crc (read-only)

The 32-bit cyclic redundancy check of the content of the mounted image file if the mounted media image was not loaded from a software list, is mounted read-only and is not a CD-ROM, or zero (0) otherwise.

image.loaded_through_softlist (read-only)

A Boolean indicating whether the mounted media image was loaded from a software list, or false if no media image is mounted.

image.software_list_name (read-only)

The short name of the software list if the mounted media image was loaded from a software list.

image.software_longname (read-only)

The full name of the software item if the mounted media image was loaded from a software list, or nil otherwise.

image.software_publisher (read-only)

The publisher of the software item if the mounted media image was loaded from a software list, or nil otherwise.

image.software_year (read-only)

The release year of the software item if the mounted media image was loaded from a software list, or nil otherwise.

image.software_parent (read-only)

The short name of the parent software item if the mounted media image was loaded from a software list, or nil otherwise.

image.device (read-only)

The underlying device.

Slot device interface

Wraps MAME’s device_slot_interface class which is a mix-in implemented by devices that instantiate a user-specified child device.

Instantiation

manager.machine.slots[tag]

Gets an slot device by tag relative to the root machine device, or nil if no such device exists or it is not a slot device.

Properties

slot.fixed (read-only)

A Boolean indicating whether this is a slot with a card specified in machine configuration that cannot be changed by the user.

slot.has_selectable_options (read-only)

A Boolean indicating whether the slot has any user-selectable options (as opposed to options that can only be selected programmatically, typically for fixed slots or to load media images).

slot.options[] (read-only)

The slot options describing the child devices that can be instantiated by the slot, indexed by option value. The at and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

slot.device (read-only)

The underlying device.

Media image format

Wraps MAME’s image_device_format class, which describes a media file format supported by a media image device.

Instantiation

manager.machine.images[tag].formatlist[name]

Gets a media image format supported by a given device by name.

Properties

format.name (read-only)

An abbreviated name used to identify the format. This often matches the primary filename extension used for the format.

format.description (read-only)

The full display name of the format.

format.extensions[] (read-only)

Yields a table of filename extensions used for the format.

format.option_spec (read-only)

A string describing options available when creating a media image using this format. The string is not intended to be human-readable.

Slot option

Wraps MAME’s device_slot_interface::slot_option class, which represents a child device that a slot device can be configured to instantiate.

Instantiation

manager.machine.slots[tag].options[name]

Gets a slot option for a given slot device by name (i.e. the value used to select the option).

Properties

option.name (read-only)

The name of the slot option. This is the value used to select this option on the command line or in an INI file.

option.device_fullname (read-only)

The full display name of the device type instantiated by this option.

option.device_shortname (read-only)

The short name of the device type instantiated by this option.

option.selectable (read-only)

A Boolean indicating whether the option may be selected by the user (options that are not user-selectable are typically used for fixed slots or to load media images).

option.default_bios (read-only)

The default BIOS setting for the device instantiated using this option, or nil if the default BIOS specified in the device’s ROM definitions will be used.

option.clock (read-only)

The configured clock frequency for the device instantiated using this option. This is an unsigned 32-bit integer. If the eight most-significant bits are all set, it is a ratio of the parent device’s clock frequency, with the numerator in bits 12-23 and the denominator in bits 0-11. If the eight most-significant bits are not all set, it is a frequency in Hertz.

Memory system

MAME’s Lua interface exposes various memory system objects, including address spaces, memory shares, memory banks, and memory regions. Scripts can read from and write to the emulated memory system.

Memory manager

Wraps MAME’s memory_manager class, which allows the memory shares, banks and regions in a system to be enumerated.

Instantiation

manager.machine.memory

Gets the global memory manager instance for the emulated system.

Properties

memory.shares[]

The memory shares in the system, indexed by absolute tag. The at and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

memory.banks[]

The memory banks in the system, indexed by absolute tag. The at and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

memory.regions[]

The memory regions in the system, indexed by absolute tag. The at and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

Address space

Wraps MAME’s address_space class, which represent’s an address space belonging to a device.

Instantiation

manager.machine.devices[tag].spaces[name]

Gets the address space with the specified name for a given device. Note that names are specific to the device type.

Methods

space:read_i{8,16,32,64}(addr)

Reads a signed integer value of the size in bits from the specified address.

space:read_u{8,16,32,64}(addr)

Reads an unsigned integer value of the size in bits from the specified address.

space:write_i{8,16,32,64}(addr, val)

Writes a signed integer value of the size in bits to the specified address.

space:write_u{8,16,32,64}(addr, val)

Writes an unsigned integer value of the size in bits to the specified address.

space:readv_i{8,16,32,64}(addr)

Reads a signed integer value of the size in bits from the specified virtual address. The address is translated with the debug read intent. Returns zero if address translation fails.

space:readv_u{8,16,32,64}(addr)

Reads an unsigned integer value of the size in bits from the specified virtual address. The address is translated with the debug read intent. Returns zero if address translation fails.

space:writev_i{8,16,32,64}(addr, val)

Writes a signed integer value of the size in bits to the specified virtual address. The address is translated with the debug write intent. Does not write if address translation fails.

space:writev_u{8,16,32,64}(addr, val)

Writes an unsigned integer value of the size in bits to the specified virtual address. The address is translated with the debug write intent. Does not write if address translation fails.

space:read_direct_i{8,16,32,64}(addr)

Reads a signed integer value of the size in bits from the specified address one byte at a time by obtaining a read pointer for each byte address. If a read pointer cannot be obtained for a byte address, the corresponding result byte will be zero.

space:read_direct_u{8,16,32,64}(addr)

Reads an unsigned integer value of the size in bits from the specified address one byte at a time by obtaining a read pointer for each byte address. If a read pointer cannot be obtained for a byte address, the corresponding result byte will be zero.

space:write_direct_i{8,16,32,64}(addr, val)

Writes a signed integer value of the size in bits to the specified address one byte at a time by obtaining a write pointer for each byte address. If a write pointer cannot be obtained for a byte address, the corresponding byte will not be written.

space:write_direct_u{8,16,32,64}(addr, val)

Writes an unsigned integer value of the size in bits to the specified address one byte at a time by obtaining a write pointer for each byte address. If a write pointer cannot be obtained for a byte address, the corresponding byte will not be written.

space:read_range(start, end, width, [step])

Reads a range of addresses as a binary string. The end address must be greater than or equal to the start address. The width must be 8, 16, 30 or 64. If the step is provided, it must be a positive number of elements.

Properties

space.name (read-only)

The display name for the address space.

space.shift (read-only)

The address granularity for the address space specified as the shift required to translate a byte address to a native address. Positive values shift towards the most significant bit (left) and negative values shift towards the least significant bit (right).

space.index (read-only)

The zero-based space index. Some space indices have special meanings for the debugger.

space.address_mask (read-only)

The address mask for the space.

space.data_width (read-only)

The data width for the space in bits.

space.endianness (read-only)

The Endianness of the space ("big" or "little").

space.map (read-only)

The configured address map for the space or nil.

Address map

Wraps MAME’s address_map class, used to configure handlers for an address space.

Instantiation

manager.machine.devices[tag].spaces[name].map

Gets the configured address map for an address space, or nil if no map is configured.

Properties

map.spacenum (read-only)

The address space number of the address space the map is associated with.

map.device (read-only)

The device that owns the address space the map is associated with.

map.unmap_value (read-only)

The constant value to return from unmapped reads.

map.global_mask (read-only)

Global mask to be applied to all addresses when accessing the space.

map.entries[] (read-only)

The configured entries in the address map. Uses 1-based integer indices. The index operator and the at method have O(n) complexity.

Address map entry

Wraps MAME’s address_map_entry class, representing an entry in a configured address map.

Instantiation

manager.machine.devices[tag].spaces[name].map.entries[index]

Gets an entry from the configured map for an address space.

Properties

entry.address_start (read-only)

Start address of the entry’s range.

entry.address_end (read-only)

End address of the entry’s range (inclusive).

entry.address_mirror (read-only)

Address mirror bits.

entry.address_mask (read-only)

Address mask bits. Only valid for handlers.

entry.mask (read-only)

Lane mask, indicating which data lines on the bus are connected to the handler.

entry.cswidth (read-only)

The trigger width for a handler that isn’t connected to all the data lines.

entry.read (read-only)

Additional data for the read handler.

entry.write (read-only)

Additional data for the write handler.

entry.share (read-only)

Memory share tag for making RAM entries accessible or nil.

entry.region (read-only)

Explicit memory region tag for ROM entries, or nil. For ROM entries, nil infers the region from the device tag.

entry.region_offset (read-only)

Starting offset in memory region for ROM entries.

Address map handler data

Wraps MAME’s map_handler_data class, which provides configuration data to handlers in address maps.

Instantiation

manager.machine.devices[tag].spaces[name].map.entries[index].read

Gets the read handler data for an address map entry.

manager.machine.devices[tag].spaces[name].map.entries[index].write

Gets the write handler data for an address map entry.

Properties

data.handlertype (read-only)

Handler type. Will be one of "none", "ram", "rom", "nop", "unmap", "delegate", "port", "bank", "submap", or "unknown". Note that multiple handler type values can yield "delegate" or "unknown".

data.bits (read-only)

Data width for the handler in bits.

data.name (read-only)

Display name for the handler, or nil.

data.tag (read-only)

Tag for I/O ports and memory banks, or nil.

Memory share

Wraps MAME’s memory_share class, representing a named allocated memory zone.

Instantiation

manager.machine.memory.shares[tag]

Gets a memory share by absolute tag, or nil if no such memory share exists.

manager.machine.devices[tag]:memshare(tag)

Gets a memory share by tag relative to a device, or nil if no such memory share exists.

Methods

share:read_i{8,16,32,64}(offs)

Reads a signed integer value of the size in bits from the specified offset in the memory share.

share:read_u{8,16,32,64}(offs)

Reads an unsigned integer value of the size in bits from the specified offset in the memory share.

share:write_i{8,16,32,64}(offs, val)

Writes a signed integer value of the size in bits to the specified offset in the memory share.

share:write_u{8,16,32,64}(offs, val)

Writes an unsigned integer value of the size in bits to the specified offset in the memory share.

Properties

share.tag (read-only)

The absolute tag of the memory share.

share.size (read-only)

The size of the memory share in bytes.

share.length (read-only)

The length of the memory share in native width elements.

share.endianness (read-only)

The Endianness of the memory share ("big" or "little").

share.bitwidth (read-only)

The native element width of the memory share in bits.

share.bytewidth (read-only)

The native element width of the memory share in bytes.

Memory bank

Wraps MAME’s memory_bank class, representing a named memory zone indirection.

Instantiation

manager.machine.memory.banks[tag]

Gets a memory region by absolute tag, or nil if no such memory bank exists.

manager.machine.devices[tag]:membank(tag)

Gets a memory region by tag relative to a device, or nil if no such memory bank exists.

Properties

bank.tag (read-only)

The absolute tag of the memory bank.

bank.entry (read/write)

The currently selected zero-based entry number.

Memory region

Wraps MAME’s memory_region class, representing a memory region used to store read-only data like ROMs or the result of fixed decryptions.

Instantiation

manager.machine.memory.regions[tag]

Gets a memory region by absolute tag, or nil if no such memory region exists.

manager.machine.devices[tag]:memregion(tag)

Gets a memory region by tag relative to a device, or nil if no such memory region exists.

Methods

region:read_i{8,16,32,64}(offs)

Reads a signed integer value of the size in bits from the specified offset in the memory region.

region:read_u{8,16,32,64}(offs)

Reads an unsigned integer value of the size in bits from the specified offset in the memory region.

region:write_i{8,16,32,64}(offs, val)

Writes a signed integer value of the size in bits to the specified offset in the memory region.

region:write_u{8,16,32,64}(offs, val)

Writes an unsigned integer value of the size in bits to the specified offset in the memory region.

Properties

region.tag (read-only)

The absolute tag of the memory region.

region.size (read-only)

The size of the memory region in bytes.

region.length (read-only)

The length of the memory region in native width elements.

region.endianness (read-only)

The Endianness of the memory region ("big" or "little").

region.bitwidth (read-only)

The native element width of the memory region in bits.

region.bytewidth (read-only)

The native element width of the memory region in bytes.

Input system

Allows scripts to get input from the user, and access I/O ports in the emulated system.

I/O port manager

Wraps MAME’s ioport_manager class, which provides access to emulated I/O ports and handles input configuration.

Instantiation

manager.machine.ioport

Gets the global I/O port manager instance for the emulated machine.

Methods

ioport:count_players()

Returns the number of player controllers in the system.

ioport:type_pressed(type, [player])

Returns a Boolean indicating whether the specified input is currently pressed. The input port type is an enumerated value. The player number is a zero-based index. If the player number is not supplied, it is assumed to be zero.

ioport:type_name(type, [player])

Returns the display name for the specified input type and player number. The input type is an enumerated value. The player number is a zero-based index. If the player number is not supplied, it is assumed to be zero.

ioport:type_group(type, player)

Returns the input group for the specified input type and player number. The input type is an enumerated value. The player number is a zero-based index. Returns an integer giving the grouping for the input. If the player number is not supplied, it is assumed to be zero.

This should be called with values obtained from I/O port fields to provide canonical grouping in an input configuration UI.

ioport:type_seq(type, [player], [seqtype])

Get the configured input sequence for the specified input type, player number and sequence type. The input type is an enumerated value. The player number is a zero-based index. If the player number is not supplied, it is assumed to be zero. If the sequence type is supplied, it must be "standard", "increment" or "decrement"; if it is not supplied, it is assumed to be "standard".

This provides access to general input configuration.

ioport:token_to_input_type(string)

Returns the input type and player number for the specified input type token.

ioport:input_type_to_token(type, [player])

Returns the token string for the specified input type and player number. If the player number is not supplied, it assumed to be zero.

Properties

ioport.ports[]

Gets the emulated I/O ports in the system. Keys are absolute tags. The at and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

Natural keyboard manager

Wraps MAME’s natural_keyboard class, which manages emulated keyboard and keypad inputs.

Instantiation

manager.machine.natkeyboard

Gets the global natural keyboard manager instance for the emulated machine.

Methods

natkeyboard:post(text)

Post literal text to the emulated machine. The machine must have keyboard inputs with character bindings, and the correct keyboard input device must be enabled.

natkeyboard:post_coded(text)

Post text to the emulated machine. Brace-enclosed codes are interpreted in the text. The machine must have keyboard inputs with character bindings, and the correct keyboard input device must be enabled.

The recognised codes are {BACKSPACE}, {BS}, {BKSP}, {DEL}, {DELETE}, {END}, {ENTER}, {ESC}, {HOME}, {INS}, {INSERT}, {PGDN}, {PGUP}, {SPACE}, {TAB}, {F1}, {F2}, {F3}, {F4}, {F5}, {F6}, {F7}, {F8}, {F9}, {F10}, {F11}, {F12}, and {QUOTE}.

natkeyboard:paste()

Post the contents of the host clipboard to the emulated machine. The machine must have keyboard inputs with character bindings, and the correct keyboard input device must be enabled.

natkeyboard:dump()

Returns a string with a human-readable description of the keyboard and keypad input devices in the system, whether they are enabled, and their character bindings.

Properties

natkeyboard.empty (read-only)

A Boolean indicating whether the natural keyboard manager’s input buffer is empty.

natkeyboard.full (read-only)

A Boolean indicating whether the natural keyboard manager’s input buffer is full.

natkeyboard.can_post (read-only)

A Boolean indicating whether the emulated system supports posting character data via the natural keyboard manager.

natkeyboard.is_posting (read-only)

A Boolean indicating whether posted character data is currently being delivered to the emulated system.

natkeyboard.in_use (read/write)

A Boolean indicating whether “natural keyboard” mode is enabled. When “natural keyboard” mode is enabled, the natural keyboard manager translates host character input to emulated system keystrokes.

natkeyboard.keyboards[]

Gets the keyboard/keypad input devices in the emulated system, indexed by absolute device tag. Index get has O(n) complexity; all other supported operations have O(1) complexity.

Keyboard input device

Represents a keyboard or keypad input device managed by the natural keyboard manager.

Instantiation

manager.machine.natkeyboard.keyboards[tag]

Gets the keyboard input device with the specified tag, or nil if the tag does not correspond to a keyboard input device.

Properties

keyboard.device (read-only)

The underlying device.

keyboard.tag (read-only)

The absolute tag of the underlying device.

keyboard.basetag (read-only)

The last component of the tag of the underlying device, or "root" for the root machine device.

keyboard.name (read-only)

The human-readable description of the underlying device type.

keyboard.shortname (read-only)

The identifier for the underlying device type.

keyboard.is_keypad (read-only)

A Boolean indicating whether the underlying device has keypad inputs but no keyboard inputs. This is used when determining which keyboard input devices should be enabled by default.

keyboard.enabled (read/write)

A Boolean indicating whether the device’s keyboard and/or keypad inputs are enabled.

I/O port

Wraps MAME’s ioport_port class, representing an emulated I/O port.

Instantiation

manager.machine.ioport.ports[tag]

Gets an emulated I/O port by absolute tag, or nil if the tag does not correspond to an I/O port.

manager.machine.devices[devtag]:ioport(porttag)

Gets an emulated I/O port by tag relative to a device, or nil if no such I/O port exists.

Methods

port:read()

Read the current input value. Returns a 32-bit integer.

port:write(value, mask)

Write to the I/O port output fields that are set in the specified mask. The value and mask must be 32-bit integers. Note that this does not set values for input fields.

port:field(mask)

Get the first I/O port field corresponding to the bits that are set in the specified mask, or nil if there is no corresponding field.

Properties

port.device (read-only)

The device that owns the I/O port.

port.tag (read-only)

The absolute tag of the I/O port

port.active (read-only)

A mask indicating which bits of the I/O port correspond to active fields (i.e. not unused or unassigned bits).

port.live (read-only)

The live state of the I/O port.

port.fields[] (read-only)

Gets a table of fields indexed by name.

I/O port field

Wraps MAME’s ioport_field class, representing a field within an I/O port.

Instantiation

manager.machine.ioport.ports[tag]:field[mask]

Gets a field for the given port by bit mask.

manager.machine.ioport.ports[tag].fields[name]

Gets a field for the given port by display name.

Methods

field:set_value(value)

Set the value of the I/O port field. For digital fields, the value is compared to zero to determine whether the field should be active; for analog fields, the value must be right-aligned and in the correct range.

field:set_input_seq(seqtype, seq)

Set the input sequence for the specified sequence type. This is used to configure per-machine input settings. The sequence type must be "standard", "increment" or "decrement".

field:input_seq(seq_type)

Get the configured input sequence for the specified sequence type. This gets per-machine input settings. The sequence type must be "standard", "increment" or "decrement".

field:set_default_input_seq(seq_type, seq)

Set the default input sequence for the specified sequence type. This is used to configure general input settings. The sequence type must be "standard", "increment" or "decrement".

field:default_input_seq(seq_type)

Gets the default input sequence for the specified sequence type. This is gets general input settings. The sequence type must be "standard", "increment" or "decrement".

field:keyboard_codes(shift)

Gets a table of characters corresponding to the field for the specified shift state. The shift state is a bit mask of active shift keys.

Properties

field.device (read-only)

The device that owns the port that the field belongs to.

field.port (read-only)

The I/O port that the field belongs to.

field.live (read-only)

The live state of the field.

field.type (read-only)

The input type of the field. This is an enumerated value.

field.name (read-only)

The display name for the field.

field.default_name (read-only)

The name for the field from the emulated system’s configuration (cannot be overridden by scripts or plugins).

field.player (read-only)

Zero-based player number for the field.

field.mask (read-only)

Bits in the I/O port corresponding to this field.

field.defvalue (read-only)

The field’s default value

field.sensitivity (read-only)

The sensitivity or gain for analog fields

field.way (read-only)

The number of directions allowed by the restrictor plate/gate for a digital joystick, or zero (0) for other inputs.

field.type_class (read-only)

The type class for the input field – one of "keyboard", "controller", "config", "dipswitch" or "misc".

field.is_analog (read-only)

A Boolean indicating whether the field is an analog axis or positional control.

field.is_digital_joystick (read-only)

A Boolean indicating whether the field corresponds to a digital joystick switch.

field.enabled (read-only)

A Boolean indicating whether the field is enabled.

field.optional (read-only)

A Boolean indicating whether the field is optional and not required to use the emulated system.

field.cocktail (read-only)

A Boolean indicating whether the field is only used when the system is configured for a cocktail table cabinet.

field.toggle (read-only)

A Boolean indicating whether the field corresponds to a hardware toggle switch or push-on, push-off button.

field.rotated (read-only)

A Boolean indicating whether the field corresponds to a control that is rotated relative its standard orientation.

field.analog_reverse (read-only)

A Boolean indicating whether the field corresponds to an analog control that increases in the opposite direction to the convention (e.g. larger values when a pedal is released or a joystick is moved to the left).

field.analog_reset (read-only)

A Boolean indicating whether the field corresponds to an incremental position input (e.g. a dial or trackball axis) that should be reset to zero for every video frame.

field.analog_wraps (read-only)

A Boolean indicating whether the field corresponds to an analog input that wraps from one end of its range to the other (e.g. an incremental position input like a dial or trackball axis).

field.analog_invert (read-only)

A Boolean indicating whether the field corresponds to an analog input that has its value ones-complemented.

field.impulse (read-only)

A Boolean indicating whether the field corresponds to a digital input that activates for a fixed amount of time.

field.crosshair_scale (read-only)

The scale factor for translating the field’s range to crosshair position. A value of one (1) translates the field’s full range to the full width or height the screen.

field.crosshair_offset (read-only)

The offset for translating the field’s range to crosshair position.

field.user_value (read/write)

The value for DIP switch or configuration settings.

field.settings[] (read-only)

Gets a table of the currently enabled settings for a DIP switch or configuration field, indexed by value.

Live I/O port field state

Wraps MAME’s ioport_field_live class, representing the live state of an I/O port field.

Instantiation

manager.machine.ioport.ports[tag]:field(mask).live

Gets the live state for an I/O port field.

Properties

live.name

Display name for the field.

Input manager

Wraps MAME’s input_manager class, which reads host input devices and checks whether configured inputs are active.

Instantiation

manager.machine.input

Gets the global input manager instance for the emulated system.

Methods

input:code_value(code)

Gets the current value for the host input corresponding to the specified code. Returns a signed integer value, where zero is the neutral position.

input:code_pressed(code)

Returns a Boolean indicating whether the host input corresponding to the specified code has a non-zero value (i.e. it is not in the neutral position).

input:code_pressed_once(code)

Returns a Boolean indicating whether the host input corresponding to the specified code has moved away from the neutral position since the last time it was checked using this function. The input manager can track a limited number of inputs this way.

input:code_name(code)

Get display name for an input code.

input:code_to_token(code)

Get token string for an input code. This should be used when saving configuration.

input:code_from_token(token)

Convert a token string to an input code. Returns the invalid input code if the token is not valid or belongs to an input device that is not present.

input:seq_pressed(seq)

Returns a Boolen indicating whether the supplied input sequence is currently pressed.

input:seq_clean(seq)

Remove invalid elements from the supplied input sequence. Returns the new, cleaned input sequence.

input:seq_name(seq)

Get display text for an inptu sequence.

input:seq_to_tokens(seq)

Convert an input sequence to a token string. This should be used when saving configuration.

input:seq_from_tokens(tokens)

Convert a token string to an input sequence. This should be used when loading configuration.

input:axis_code_poller()

Returns an input code poller for obtaining an analog host input code.

input:switch_code_poller()

Returns an input code poller for obtaining a host switch input code.

input:keyboard_code_poller()

Returns an input code poller for obtaining a host switch input code that only considers keyboard input devices.

input:axis_sequence_poller()

Returns an input sequence poller for obtaining an input sequence for configuring an analog input.

input:axis_sequence_poller()

Returns an input sequence poller for obtaining an input sequence for configuring a digital input.

Properties

input.device_classes[] (read-only)

Gets a table of host input device classes indexed by name.

Input code poller

Wraps MAME’s input_code_poller class, used to poll for host inputs being activated.

Instantiation

manager.machine.input:axis_code_poller()

Returns an input code poller that polls for analog inputs being activated.

manager.machine.input:switch_code_poller()

Returns an input code poller that polls for host switch inputs being activated.

manager.machine.input:keyboard_code_poller()

Returns an input code poller that polls for host switch inputs being activated, only considering keyboard input devices.

Methods

poller:reset()

Resets the polling logic. Active switch inputs are cleared and initial analog input positions are set.

poller:poll()

Returns an input code corresponding to the first relevant host input that has been activated since the last time the method was called. Returns the invalid input code if no relevant input has been activated.

Input sequence poller

Wraps MAME’s input_sequence_poller poller class, which allows users to assign host input combinations to emulated inputs and other actions.

Instantiation

manager.machine.input:axis_sequence_poller()

Returns an input sequence poller for assigning host inputs to an analog input.

manager.machine.input:switch_sequence_poller()

Returns an input sequence poller for assigning host inputs to a switch input.

Methods

poller:start([seq])

Start polling. If a sequence is supplied, it is used as a starting sequence: for analog inputs, the user can cycle between the full range, and the positive and negative portions of an axis; for switch inputs, an “or” code is appended and the user can add an alternate host input combination.

poller:poll()

Polls for for user input and updates the sequence if appropriate. Returns a Boolean indicating whether sequence input is complete. If this method returns false, you should continue polling.

Properties

poller.sequence (read-only)

The current input sequence. This is updated while polling. It is possible for the sequence to become invalid.

poller.valid (read-only)

A Boolean indicating whether the current input sequence is valid.

poller.modified (read-only)

A Boolean indicating whether the sequence was changed by any user input since starting polling.

Host input device class

Wraps MAME’s input_class class, representing a category of host input devices (e.g. keyboards or joysticks).

Instantiation

manager.machine.input.device_classes[name]

Gets an input device class by name.

Properties

devclass.name (read-only)

The device class name.

devclass.enabled (read-only)

A Boolean indicating whether the device class is enabled.

devclass.multi (read-only)

A Boolean indicating whether the device class supports multiple devices, or inputs from all devices in the class are combined and treated as a single device.

devclass.devices[] (read-only)

Gets a table of host input devices in the class. Keys are one-based indices.

Host input device

Wraps MAME’s input_device class, representing a host input device.

Instantiation

manager.machine.input.device_classes[name].devices[index]

Gets a specific host input device.

Properties

inputdev.name (read-only)

Display name for the device. This is not guaranteed to be unique.

inputdev.id (read-only)

Unique identifier string for the device. This may not be human-readable.

inputdev.devindex (read-only)

Device index within the device class. This is not necessarily the same as the index in the devices property of the device class – the devindex indices may not be contiguous.

inputdev.items (read-only)

Gets a table of input items, indexed by item ID. The item ID is an enumerated value.

Host input device item

Wraps MAME’s input_device_item class, representing a single host input (e.g. a key, button, or axis).

Instantiation

manager.machine.input.device_classes[name].devices[index].items[id]

Gets an individual host input item. The item ID is an enumerated value.

Properties

item.name (read-only)

The display name of the input item. Note that this is just the name of the item itself, and does not include the device name. The full display name for the item can be obtained by calling the code_name method on the input manager with the item’s code.

item.code (read-only)

The input item’s identification code. This is used by several input manager methods.

item.token (read-only)

The input item’s token string. Note that this is a token fragment for the item itself, and does not include the device portion. The full token for the item can be obtained by calling the code_to_token method on the input manager with the item’s code.

item.current (read-only)

The item’s current value. This is a signed integer where zero is the neutral position.

UI input manager

Wraps MAME’s ui_input_manager class, which is used for high-level input.

Instantiation

manager.machine.uiinput

Gets the global UI input manager instance for the machine.

Methods

uiinput:find_mouse()

Returns host system mouse pointer X position, Y position, button state, and the render target it falls in. The position is in host pixels, where zero is at the top/left. The button state is a Boolean indicating whether the primary mouse button is pressed.

If the mouse pointer is not over one of MAME’s windows, this may return the position and render target from when the mouse pointer was most recently over one of MAME’s windows. The render target may be nil if the mouse pointer is not over one of MAME’s windows.

uiinput:pressed(type)

Returns a Boolean indicating whether the specified UI input has been pressed. The input type is an enumerated value.

uiinput:pressed_repeat(type, speed)

Returns a Boolean indicating whether the specified UI input has been pressed or auto-repeat has been triggered at the specified speed. The input type is an enumerated value; the speed is an interval in sixtieths of a second.

Properties

uiinput.presses_enabled (read/write)

Whether the UI input manager will check for UI inputs frame updates.

Render system

The render system is responsible for drawing what you see in MAME’s windows, including emulated screens, artwork, and UI elements.

Render bounds

Wraps MAME’s render_bounds class, which represents a rectangle using floating-point coordinates.

Instantiation

emu.render_bounds()

Creates a render bounds object representing a unit square, with top left corner at (0, 0) and bottom right corner at (1, 1). Note that render target coordinates don’t necessarily have equal X and Y scales, so this may not represent a square in the final output.

emu.render_bounds(left, top, right, bottom)

Creates a render bounds object representing a rectangle with top left corner at (x0, y0) and bottom right corner at (x1, y1).

The arguments must all be floating-point numbers.

Methods

bounds:includes(x, y)

Returns a Boolean indicating whether the specified point falls within the rectangle. The rectangle must be normalised for this to work (right greater than left and bottom greater than top).

The arguments must both be floating-point numbers.

bounds:set_xy(left, top, right, bottom)

Set the rectangle’s position and size in terms of the positions of the edges.

The arguments must all be floating-point numbers.

bounds:set_wh(left, top, width, height)

Set the rectangle’s position and size in terms of the top top left corner position, and the width and height.

The arguments must all be floating-point numbers.

Properties

bounds.x0 (read/write)

The leftmost coordinate in the rectangle (i.e. the X coordinate of the left edge or the top left corner).

bounds.x1 (read/write)

The rightmost coordinate in the rectangle (i.e. the X coordinate of the right edge or the bottom right corner).

bounds.y0 (read/write)

The topmost coordinate in the rectangle (i.e. the Y coordinate of the top edge or the top left corner).

bounds.y1 (read/write)

The bottommost coordinate in the rectangle (i.e. the Y coordinate of the bottom edge or the bottom right corner).

bounds.width (read/write)

The width of the rectangle. Setting this property changes the position of the rightmost edge.

bounds.height (read/write)

The height of the rectangle. Setting this property changes the position of the bottommost edge.

bounds.aspect (read-only)

The width-to-height aspect ratio of the rectangle. Note that this is often in render target coordinates which don’t necessarily have equal X and Y scales. A rectangle representing a square in the final output doesn’t necessarily have an aspect ratio of 1.

Render colour

Wraps MAME’s render_color class, which represents an ARGB (alpha, red, green, blue) format colour. Channels are floating-point values ranging from zero (0, transparent alpha or colour off) to one (1, opaque or full colour intensity). Colour channel values are not pre-multiplied by the alpha channel value.

Instantiation

emu.render_color()

Creates a render colour object representing opaque white (all channels set to 1). This is the identity value – ARGB multiplication by this value will not change a colour.

emu.render_color(a, r, g, b)

Creates a render colour object with the specified alpha, red, green and blue channel values.

The arguments must all be floating-point numbers in the range from zero (0) to one (1), inclusive.

Methods

color:set(a, r, g, b)

Sets the colour object’s alpha, red, green and blue channel values.

The arguments must all be floating-point numbers in the range from zero (0) to one (1), inclusive.

Properties

color.a (read/write)

Alpha value, in the range of zero (0, transparent) to one (1, opaque).

color.r (read/write)

Red channel value, in the range of zero (0, off) to one (1, full intensity).

color.g (read/write)

Green channel value, in the range of zero (0, off) to one (1, full intensity).

color.b (read/write)

Blue channel value, in the range of zero (0, off) to one (1, full intensity).

Render manager

Wraps MAME’s render_manager class, responsible for managing render targets and textures.

Instantiation

manager.machine.render

Gets the global render manager instance for the emulation session.

Properties

render.max_update_rate (read-only)

The maximum update rate in Hertz. This is a floating-point number.

render.ui_target (read-only)

The render target used to draw the user interface (including menus, sliders and pop-up messages). This is usually the first host window or screen.

render.ui_container (read-only)

The render container used for drawing the user interface.

render.targets[] (read-only)

The list of render targets, including output windows and screens, as well as hidden render targets used for things like rendering screenshots. Uses 1-based integer indices. The index operator and the at method have O(n) complexity.

Render target

Wrap’s MAME’s render_target class, which represents a video output channel. This could be a host window or screen, or a hidden target used for rendering screenshots.

Instantiation

manager.machine.render.targets[index]

Gets a render target by index.

manager.machine.render.ui_target

Gets the render target used to display the user interface (including menus, sliders and pop-up messages). This is usually the first host window or screen.

manager.machine.video.snapshot_target

Gets the render target used to produce snapshots and video recordings.

Properties

target.index (read-only)

The 1-based index of the render target. This has O(n) complexity.

target.width (read-only)

The width of the render target in output pixels. This is an integer.

target.height (read-only)

The height of the render target in output pixels. This is an integer.

target.pixel_aspect (read-only)

The width-to-height aspect ratio of the render target’s pixels. This is a floating-point number.

target.hidden (read-only)

A Boolean indicating whether this is an internal render target that is not displayed to the user directly (e.g. the render target used to draw screenshots).

target.is_ui_target (read-only)

A Boolean indicating whether this is the render target used to display the user interface.

target.max_update_rate (read/write)

The maximum update rate for the render target in Hertz.

target.orientation (read/write)

The target orientation flags. This is an integer bit mask, where bit 0 (0x01) is set to mirror horizontally, bit 1 (0x02) is set to mirror vertically, and bit 2 (0x04) is set to mirror along the top left-bottom right diagonal.

target.view_names[]

The names of the available views for this render target. Uses 1-based integer indices. The find and index_of methods have O(n) complexity; all other supported operations have O(1) complexity.

target.current_view (read-only)

The currently selected view for the render target. This is a layout view object.

target.view_index (read/write)

The 1-based index of the selected view for this render target.

target.visibility_mask (read-only)

An integer bit mask indicating which item collections are currently visible for the current view.

target.screen_overlay (read/write)

A Boolean indicating whether screen overlays are enabled.

target.zoom_to_screen (read/write)

A Boolean indicating whether the render target is configured to scale so that the emulated screen(s) fill as much of the output window/screen as possible.

Render container

Wraps MAME’s render_container class.

Instantiation

manager.machine.render.ui_container

Gets the render container used to draw the user interface, including menus, sliders and pop-up messages.

manager.machine.screens[tag].container

Gets the render container used to draw a given screen.

Properties

container.user_settings (read/write)

The container’s user settings. This can be used to control a number of image adjustments.

container.orientation (read/write)

The container orientation flags. This is an integer bit mask, where bit 0 (0x01) is set to mirror horizontally, bit 1 (0x02) is set to mirror vertically, and bit 2 (0x04) is set to mirror along the top left-bottom right diagonal.

container.xscale (read/write)

The container’s X scale factor. This is a floating-point number.

container.yscale (read/write)

The container’s Y scale factor. This is a floating-point number.

container.xoffset (read/write)

The container’s X offset. This is a floating-point number where one (1) corresponds to the X size of the container.

container.yoffset (read/write)

The container’s Y offset. This is a floating-point number where one (1) corresponds to the Y size of the container.

container.is_empty (read-only)

A Boolean indicating whether the container has no items.

Container user settings

Wraps MAME’s render_container::user_settings class, representing image adjustments applied to a render container.

Instantiation

manager.machine.screens[tag].container

Gets the current container user settings for a given screen.

Properties

settings.orientation (read/write)

The container orientation flags. This is an integer bit mask, where bit 0 (0x01) is set to mirror horizontally, bit 1 (0x02) is set to mirror vertically, and bit 2 (0x04) is set to mirror along the top left-bottom right diagonal.

settings.brightness (read/write)

The brightness adjustment applied to the container. This is a floating-point number.

settings.contrast (read/write)

The contrast adjustment applied to the container. This is a floating-point number.

settings.gamma (read/write)

The gamma adjustment applied to the container. This is a floating-point number.

settings.xscale (read/write)

The container’s X scale factor. This is a floating-point number.

settings.yscale (read/write)

The container’s Y scale factor. This is a floating-point number.

settings.xoffset (read/write)

The container’s X offset. This is a floating-point number where one (1) represents the X size of the container.

settings.yoffset (read/write)

The container’s Y offset. This is a floating-point number where one (1) represents the Y size of the container.

Layout file

Wraps MAME’s layout_file class, representing the views loaded from a layout file for use by a render target.

Instantiation

A layout file object is supplied to its layout script in the file variable. Layout file objects are not instantiated directly from Lua scripts.

Methods

layout:set_resolve_tags_callback(cb)

Set a function to perform additional tasks after the emulated machine has finished starting, tags in the layout views have been resolved, and the default view item handlers have been set up. The function must accept no arguments.

Call with nil to remove the callback.

Properties

layout.device (read-only)

The device that caused the layout file to be loaded. Usually the root machine device for external layouts.

layout.views[] (read-only)

The views created from the layout file. Views are indexed by unqualified name (i.e. the value of the name attribute). Views are ordered how they appear in the layout file when iterating or using the at method. The index get, at and index_of methods have O(n) complexity.

Note that not all views in the XML file may be created. For example views that reference screens provided by slot card devices will not be created if said slot card devices are not present in the system.

Layout view

Wraps MAME’s layout_view class, representing a view that can be displayed in a render target. Views are created from XML layout files, which may be loaded from external artwork, internal to MAME, or automatically generated based on the screens in the emulated system.

Instantiation

Layout scripts generally

manager.machine.render.targets[index].current_view

Gets the currently selected view for a given render target.

Methods

view:has_screen(screen)

Returns a Boolean indicating whether the screen is present in the view. This is true for screens that are present but not visible because the user has hidden the item collection they belong to.

view:set_prepare_items_callback(cb)

Set a function to perform additional tasks before the view items are added to the render target in preparation for drawing a video frame. The function must accept no arguments. Call with nil to remove the callback.

view:set_preload_callback(cb)

Set a function to perform additional tasks after preloading visible view items. The function must accept no arguments. Call with nil to remove the callback.

This function may be called when the user selects a view or makes an item collection visible. It may be called multiple times for a view, so avoid repeating expensive tasks.

view:set_recomputed_callback(cb)

Set a function to perform additional tasks after the view’s dimensions are recomputed. The function must accept no arguments. Call with nil to remove the callback.

View coordinates are recomputed in various events, including the window being resized, entering or leaving full-screen mode, and changing the zoom to screen area setting.

Properties

view.items[] (read-only)

The screen and layout element items in the view. This container does not support iteration by key using pairs; only iteration by index using ipairs is supported. The key is the value of the id attribute if present. Only items with id attributes can be looked up by key. The index get method has O(1) complexity, and the at and index_of methods have O(n) complexity.

view.name (read-only)

The display name for the view. This may be qualified to indicate the device that caused the layout file to be loaded when it isn’t the root machine device.

view.unqualified_name (read-only)

The unqualified name of the view, exactly as it appears in the name attribute in the XML layout file.

view.visible_screen_count (read-only)

The number of screens items currently enabled in the view.

view.effective_aspect (read-only)

The effective width-to-height aspect ratio of the view in its current configuration.

view.bounds (read-only)

A render bounds object representing the effective bounds of the view in its current configuration. The coordinates are in view units, which are arbitrary but assumed to have square aspect ratio.

view.has_art

A Boolean indicating whether the view has any non-screen items, including items that are not visible because the user has hidden the item collection that they belong to.

Layout view item

Wraps MAME’s layout_view::item class, representing an item in a view. An item is drawn as a rectangular textured surface. The texture is supplied by an emulated screen or a layout element.

Instantiation

layout.views[name].items[id]

Get a view item by ID. The item must have an id attribute in the XML layout file to be looked up by ID.

Methods

item:set_state(state)

Set the value used as the element state and animation state in the absence of bindings. The argument must be an integer.

item.set_element_state_callback(cb)

Set a function to call to obtain the element state for the item. The function must accept no arguments and return an integer. Call with nil to restore the default element state callback (based on bindings in the XML layout file).

Note that the function must not access the item’s element_state property, as this will result in infinite recursion.

This callback will not be used to obtain the animation state for the item, even if the item lacks explicit animation state bindings in the XML layout file.

item.set_animation_state_callback(cb)

Set a function to call to obtain the animation state for the item. The function must accept no arguments and return an integer. Call with nil to restore the default animation state callback (based on bindings in the XML layout file).

Note that the function must not access the item’s animation_state property, as this will result in infinite recursion.

item.set_bounds_callback(cb)

Set a function to call to obtain the bounds for the item. The function must accept no arguments and return a render bounds object in render target coordinates. Call with nil to restore the default bounds callback (based on the item’s animation state and bounds child elements in the XML layout file).

Note that the function must not access the item’s bounds property, as this will result in infinite recursion.

item.set_color_callback(cb)

Set a function to call to obtain the multiplier colour for the item. The function must accept no arguments and return a render colour object. Call with nil to restore the default colour callback (based on the item’s animation state and color child elements in the XML layout file).

Note that the function must not access the item’s color property, as this will result in infinite recursion.

Properties

item.id (read-only)

Get the optional item identifier. This is the value of the id attribute in the XML layout file if present, or nil.

item.bounds_animated (read-only)

A Boolean indicating whether the item’s bounds depend on its animation state.

item.color_animated (read-only)

A Boolean indicating whether the item’s colour depends on its animation state.

item.bounds (read-only)

The item’s bounds for the current state. This is a render bounds object in render target coordinates.

item.color (read-only)

The item’s colour for the current state. The colour of the screen or element texture is multiplied by this colour. This is a render colour object.

item.blend_mode (read-only)

Get the item’s blend mode. This is an integer value, where 0 means no blending, 1 means alpha blending, 2 means RGB multiplication, 3 means additive blending, and -1 allows the items within a container to specify their own blending modes.

item.orientation (read-only)

Get the item orientation flags. This is an integer bit mask, where bit 0 (0x01) is set to mirror horizontally, bit 1 (0x02) is set to mirror vertically, and bit 2 (0x04) is set to mirror along the top left-bottom right diagonal.

item.element_state (read-only)

Get the current element state. This will call the element state callback function to handle bindings.

item.animation_state (read-only)

Get the current animation state. This will call the animation state callback function to handle bindings.

Debugger

Some of MAME’s core debugging features can be controlled from Lua script. The debugger must be enabled to use the debugging features (usually by passing -debug on the command line).

Debugger manager

Wraps MAME’s debugger_manager class, providing the main interface to control the debugger.

Instantiation

manager.machine.debugger

Returns the global debugger manager instance, or nil if the debugger is not enabled.

Methods

debugger:command(str)

Execute a debugger console command. The argument is the command string. The output is sent to both the debugger console and the Lua console.

Properties

debugger.consolelog[] (read-only)

The lines in the console log (output from debugger commands). This container only supports index and length operations.

debugger.errorlog[] (read-only)

The lines in the error log (logerror output). This container only supports index and length operations.

debugger.visible_cpu (read/write)

The CPU device with debugger focus. Changes become visible in the debugger console after the next step. Setting to a device that is not a CPU has no effect.

debugger.execution_state (read/write)

Either "run" if the emulated system is running, or "stop" if it is stopped in the debugger.

Device debugger interface

Wraps MAME’s device_debug class, providing the debugger interface to an emulated CPU device.

Instantiation

manager.machine.devices[tag]:debug()

Returns the debugger interface for an emulated CPU device, or nil if the device is not a CPU.

Methods

debug:step([cnt])

Step by the specified number of instructions. If the instruction count is not provided, it defaults to a single instruction.

debug:go()

Run the emulated CPU.

debug:bpset(addr, [cond], [act])

Set a breakpoint at the specified address, with an optional condition and action. If the action is not specified, it defaults to just breaking into the debugger. Returns the breakpoint number for the new breakpoint.

If specified, the condition must be a debugger expression that will be evaluated each time the breakpoint is hit. Execution will only be stopped if the expression evaluates to a non-zero value. If the condition is not specified, it defaults to always active.

debug:bpenable([bp])

Enable the specified breakpoint, or all breakpoints for the device if no breakpoint number is specified. Returns whether the specified number matched a breakpoint if a breakpoint number is specified, or nil if no breakpoint number is specified.

debug:bpdisable([bp])

Disable the specified breakpoint, or all breakpoints for the device if no breakpoint number is specified. Returns whether the specified number matched a breakpoint if a breakpoint number is specified, or nil if no breakpoint number is specified.

debug:bpclear([bp])

Clear the specified breakpoint, or all breakpoints for the device if no breakpoint number is specified. Returns whether the specified number matched a breakpoint if a breakpoint number is specified, or nil if no breakpoint number is specified.

debug:bplist()

Returns a table of breakpoints for the device. The keys are the breakpoint numbers, and the values are breakpoint objects.

debug:wpset(space, type, addr, len, [cond], [act])

Set a watchpoint over the specified address range, with an optional condition and action. The type must be "r", "w" or "rw" for a read, write or read/write breakpoint. If the action is not specified, it defaults to just breaking into the debugger. Returns the watchpoint number for the new watchpoint.

If specified, the condition must be a debugger expression that will be evaluated each time the breakpoint is hit. Execution will only be stopped if the expression evaluates to a non-zero value. For all watchpoints, a wpaddr variable is set to the address that triggered the watchpoint. When a watchpoint is triggered by a write, a wpdata variable is set to the data being written. If the condition is not specified, it defaults to always active.

debug:wpenable([wp])

Enable the specified watchpoint, or all watchpoints for the device if no watchpoint number is specified. Returns whether the specified number matched a watchpoint if a watchpoint number is specified, or nil if no watchpoint number is specified.

debug:wpdisable([wp])

Disable the specified watchpoint, or all watchpoints for the device if no watchpoint number is specified. Returns whether the specified number matched a watchpoint if a watchpoint number is specified, or nil if no watchpoint number is specified.

debug:wpclear([wp])

Clear the specified watchpoint, or all watchpoints for the device if no watchpoint number is specified. Returns whether the specified number matched a watchpoint if a watchpoint number is specified, or nil if no watchpoint number is specified.

debug:wplist(space)

Returns a table of watchpoints for the specified address space of the device. The keys are the watchpoint numbers, and the values are watchpoint objects.

Breakpoint

Wraps MAME’s debug_breakpoint class, representing a breakpoint for an emulated CPU device.

Instantiation

manager.machine.devices[tag]:debug():bplist()[bp]

Gets the specified breakpoint for an emulated CPU device, or nil if no breakpoint corresponds to the specified index.

Properties

breakpoint.index (read-only)

The breakpoint’s index. The can be used to enable, disable or clear the breakpoint via the CPU debugger interface.

breakpoint.enabled (read-only)

A Boolean indicating whether the breakpoint is currently enabled.

breakpoint.address (read-only)

The breakpoint’s address.

breakpoint.condition (read-only)

A debugger expression evaluated each time the breakpoint is hit. The action will only be triggered if this expression evaluates to a non-zero value. An empty string if no condition was specified.

breakpoint.action (read-only)

An action the debugger will run when the breakpoint is hit and the condition evaluates to a non-zero value. An empty string if no action was specified.

Watchpoint

Wraps MAME’s debug_watchpoint class, representing a watchpoint for an emulated CPU device.

Instantiation

manager.machine.devices[tag]:debug():wplist(space)[wp]

Gets the specified watchpoint for an address space of an emulated CPU device, or nil if no watchpoint in the address space corresponds to the specified index.

Properties

watchpoint.index (read-only)

The watchpoint’s index. The can be used to enable, disable or clear the watchpoint via the CPU debugger interface.

watchpoint.enabled (read-only)

A Boolean indicating whether the watchpoint is currently enabled.

watchpoint.type (read-only)

Either "r", "w" or "rw" for a read, write or read/write watchpoint.

watchpoint.address (read-only)

The starting address of the watchpoint’s address range.

watchpoint.length (read-only)

The length of the watchpoint’s address range.

watchpoint.condition (read-only)

A debugger expression evaluated each time the watchpoint is hit. The action will only be triggered if this expression evaluates to a non-zero value. An empty string if no condition was specified.

watchpoint.action (read-only)

An action the debugger will run when the watchpoint is hit and the condition evaluates to a non-zero value. An empty string if no action was specified.