Mesen Lua API reference_Mesen Lua 函数库

--Mesen Lua 函数库.
Mesen Lua API reference

Important: This API is similar but not completely compatible with the old Mesen 0.9.x (or Mesen-S) Lua APIs.

Generated on Sep 6 2024, 08:54:50 for Mesen 2.0.0.
Callbacks
addEventCallback

Syntax
emu.addEventCallback(callback, eventType)

Parameters
callback - Function
Lua function to call when the event occurs
eventType - Enum (eventType)
Event type

Return value
Int - Value that can be used to remove the callback by calling emu.removeEventCallback().

Description
Registers a callback function to be called whenever the specified event occurs.
The callback function receives 1 parameter ("cpuType") which is an enum value (emu.cpuType) which indicates which CPU triggered the event (useful to distinguish between identical events triggered by different CPUs, e.g Super Game Boy).
addMemoryCallback

Syntax
emu.addMemoryCallback(callback, callbackType, startAddress, endAddress, cpuType, memoryType)

Parameters
callback - Function
Lua function to call when the event occurs
callbackType - Enum (callbackType)
Callback type
startAddress - Int
Start of the address range
endAddress - Int (default: start address)
End of the address range
cpuType - Enum (cpuType) (default: main CPU)
CPU used for the callback
memoryType - Enum (memType) (default: main CPU memory)
Memory type for the callback

Return value
Int - Value that can be used to remove the callback by calling emu.removeMemoryCallback().

Description
Registers a callback function to be called whenever the specified event occurs.
The callback function receives 2 parameters ("address" and "value") that correspond to the address being written to or read from, and the value that is being read/written.

For reads, the callback is called after the read is performed.
For writes, the callback is called before the write is performed.

If the callback returns an integer value, it will replace the value - you can alter the results of read/write operation by using this.
removeEventCallback

Syntax
emu.removeEventCallback(reference, eventType)

Parameters
reference - Int
Value returned by the call to emu.addEventCallback()
eventType - Enum (eventType)
Event type

Return value
<none>

Description
Removes a previously registered callback function.
removeMemoryCallback

Syntax
emu.removeMemoryCallback(reference, callbackType, startAddress, endAddress, cpuType, memoryType)

Parameters
reference - Int
Value returned by the call to emu.addMemoryCallback()
callbackType - Enum (callbackType)
Callback type
startAddress - Int
Start of the address range
endAddress - Int (default: start address)
End of the address range
cpuType - Enum (cpuType) (default: main CPU)
CPU used for the callback
memoryType - Enum (memType) (default: main CPU memory)
Memory type

Return value
<none>

Description
Removes a previously registered callback function.
Drawing
clearScreen

Syntax
emu.clearScreen()

Parameters
<none>

Return value
<none>

Description
Removes all drawn shapes from the screen.
drawLine

Syntax
emu.drawLine(x, y, x2, y2, color, duration, delay)

Parameters
x - Int
X position (start of line)
y - Int
Y position (start of line)
x2 - Int
X position (end of line)
y2 - Int
Y position (end of line)
color - Int (ARGB) (default: 0xFFFFFF (white))
Color
duration - Int (default: 1)
Number of frames to display
delay - Int (default: 0)
Number of frames to wait before drawing the line

Return value
<none>

Description
Draws a line between (x, y) to (x2, y2) using the specified color for a specific number of frames.
drawPixel

Syntax
emu.drawPixel(x, y, color, duration, delay)

Parameters
x - Int
X position
y - Int
Y position
color - Int (ARGB)
Color
duration - Int (default: 1)
Number of frames to display
delay - Int (default: 0)
Number of frames to wait before drawing the pixel

Return value
<none>

Description
Draws a pixel at the specified (x, y) coordinates using the specified color for a specific number of frames.
drawRectangle

Syntax
emu.drawRectangle(x, y, width, height, color, fill, duration, delay)

Parameters
x - Int
X position
y - Int
Y position
width - Int
Width
height - Int
Height
color - Int (ARGB) (default: 0xFFFFFF (white))
Color
fill - Boolean (default: false)
Whether or not to draw an outline, or a filled rectangle.
duration - Int (default: 1)
Number of frames to display
delay - Int (default: 0)
Number of frames to wait before drawing the rectangle
重试

错误原因

Return value
<none>

Description
Draws a rectangle between (x, y) to (x+width, y+height) using the specified color for a specific number of frames. If fill is false, only the rectangle's outline will be drawn.
drawString

Syntax
emu.drawString(x, y, text, textColor, backgroundColor, maxWidth, duration, delay)

Parameters
x - Int
X position
y - Int
Y position
text - String
Text to display
textColor - Int (ARGB) (default: 0xFFFFFF (white))
Color to use for the text
backgroundColor - Int (ARGB) (default: 0 (transparent))
Color to use for the background
maxWidth - Int (default: 0)
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Max width (pixels) - wraps to next line when reached
duration - Int (default: 1)
Number of frames to display
delay - Int (default: 0)
Number of frames to wait before drawing the text

Return value
<none>

Description
Draws text at (x, y) using the specified text and colors for a specific number of frames.
getDrawSurfaceSize

Syntax
emu.getDrawSurfaceSize(surface)

Parameters
surface - Enum (drawSurface) (default: current draw surface)
Draw surface

Return value
Table - { width = int, height = int, visibleWidth = int, visibleHeight = int, overscan = { top = int, bottom = int, left = int, right = int } }

Description
Returns a table containing the full size, visible size and overscan size for the selected draw surface.
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错误原因
getPixel

Syntax
emu.getPixel(x, y)

Parameters
x - Int
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X position
y - Int
Y position

Return value
Int - ARGB color

Description
Returns the color (in ARGB format) of the screen's output for the specified coordinates.
getScreenBuffer

Syntax
emu.getScreenBuffer()

Parameters
<none>

Return value
Array - Array of ARGB values

Description
Returns an array of ARGB values with the contents of the console's screen - can be used with emu.setScreenBuffer() to modify the screen's contents.

Note: The size of the array varies based on the console, game, and sometimes scene. Use emu.getScreenSize() to get the screen's current dimensions.
getScreenSize

Syntax
emu.getScreenSize()

Parameters
<none>

Return value
Table - { width = int, height = int }

Description
Returns a table containing the size of the console's current screen output.
measureString

Syntax
emu.measureString(text, maxWidth)

Parameters
text - String
String to measure
maxWidth - Int (default: 0)
Max width (pixels) - wraps to next line when reached

Return value
Table - { width = int, height = int }

Description
Measures the specified string and returns a table containing the width and height that the string would take when drawn.
selectDrawSurface

Syntax
emu.selectDrawSurface(surface, scale)

Parameters
surface - Enum (drawSurface)
Draw surface
scale - Int (default: current scale)
Scale to use for the "scriptHud" surface (max: 4)

Return value
<none>
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Description
Selects the surface on which any subsequent draw call will be drawn to.

consoleScreen: This surface is the same as the console's output and is a fixed resolution. Anything drawn here will appear in screenshots/videos.

scriptHud: This surface is independent to the console's output and has a configurable resolution. Drawings done on this surface will not appear in screenshots/videos.

Note: setScreenBuffer always draws to the "consoleScreen" surface.
setScreenBuffer

Syntax
emu.setScreenBuffer(screenBuffer)

Parameters
screenBuffer - Array
Array of integers in ARGB format

Return value
<none>

Description
Replaces the current frame with the contents of the specified array.
Emulation
breakExecution

Syntax
emu.breakExecution()

Parameters
<none>

Return value
<none>

Description
Breaks the execution.
getState

Syntax
emu.getState()

Parameters
<none>

Return value
Table - Content varies for each console and game.

Description
Returns a table containing key-value pairs that describe the console's current state.

Note: The name of the values returned may change from one version to another. Some values may represent the emulator's internal state and may not be useful (these will be hidden in future versions.)
reset

Syntax
emu.reset()

Parameters
<none>

Return value
<none>

Description
Resets the current game. If the console does not have a reset button, this will have the same effect as power cycling.
resume

Syntax
emu.resume()

Parameters
重试


错误原因
<none>

Return value
<none>

Description
Resumes execution after a break.
rewind

Syntax
emu.rewind(seconds)

Parameters
seconds - Int
Number of seconds to rewind

Return value
<none>

Description
Instantly rewinds the emulation by the number of seconds specified.

Note: This can only be called from inside an "exec" memory callback.
setState

Syntax
emu.setState(state)

Parameters
state - Table
A key-value table containing the state to be applied.

Return value
<none>

Description
Changes the state of the emulator to match the values provided in the "state" parameter.

Note: The name of the values returned may change from one version to another. Some values may represent the emulator's internal state and should not be changed (access to these will be removed in future versions.)
step

Syntax
emu.step(count, stepType, cpuType)

Parameters
count - Int
Number of cycles/frames/etc.
stepType - Enum (stepType)
Step type
cpuType - Enum (cpuType) (default: main CPU)
CPU type

Return value
<none>

Description
Breaks the emulation's execution when the step conditions are reached.
stop

Syntax
emu.stop(exitCode)

Parameters
exitCode - Int
The exit code that the Mesen process will return.

Return value
<none>

Description
Stops the emulation and returns the specified exit code (when used with the --testRunner command line option).
Input
getInput

Syntax
emu.getInput(port, subPort)

Parameters
port - Int
Port number
subPort - Int (default: 0)
Subport number - this is used for multitap-like adapters.

Return value
Table - Content varies based on controller type.

Description
Returns a table containing the state of all buttons for the selected port/controller. The table's content varies based on the controller type.
getMouseState

Syntax
emu.getMouseState()

Parameters
<none>

Return value
Table - { x = int, y = int, relativeX = int, relativeY = int, left = bool, middle = bool, right = bool }

Description
Returns a table containing the position and the state of all 3 buttons.
isKeyPressed

Syntax
emu.isKeyPressed(keyName)

Parameters
keyName - String
Name of the key to check

Return value
Bool - The key's state (true when pressed)

Description
Returns whether or not a specific key is pressed. The "keyName" must be the same as the string shown in the UI when the key is bound to a button.
setInput

Syntax
emu.setInput(input, port, subPort)

Parameters
input - Table
Controller state to apply to the port, same format as the return value of getInput().
port - Int
Port number
subPort - Int (default: 0)
Subport number - this is used for multitap-like adapters.

Return value
<none>

Description
Sets the input state for the specified port. Buttons enabled or disabled via setInput will keep their state until the next inputPolled event.

Note: If a button's value is not specified in the "input" argument, then the player retains control of that button. For example, "emu.setInput({ select = false, start = false }, 0)" will prevent the player 1 from using both the start and select buttons, but all other buttons will still work as normal.

It is recommended to use this function within a callback for the inputPolled event. Otherwise, the inputs may not be applied before the ROM has the chance to read them.
Logging
displayMessage

Syntax
emu.displayMessage(category, text)

Parameters
category - String
The category is the portion shown between brackets
text - String
Text to show on the screen

Return value
<none>

Description
Displays a message on the main window in the format "[category] text"
getLogWindowLog

Syntax
emu.getLogWindowLog()

Parameters
<none>

Return value
String - A string containing the log shown in the log window

Description
Returns the same text as what is shown in the emulator's log window.
log

Syntax
emu.log(text)

Parameters
text - String
Text to log

Return value
<none>

Description
Logs the specified string in the script's log window - useful for debugging scripts.
Memory Access
convertAddress

Syntax
emu.convertAddress(address, memoryType, cpuType)

Parameters
address - Int
Address to convert
memoryType - Enum (memType) (default: main CPU memory)
Memory type
cpuType - Enum (cpuType) (default: main CPU)
CPU used for the conversion

Return value
Table - { address = int, memType = enum }

Description
Converts an address between CPU addressing mode and ROM/RAM addressing mode.
When a ROM/RAM address is given, a CPU address matching that value is returned, if the address is mapped.
When a CPU address is given, the corresponding ROM/RAM address is returned, if the address is mapped to ROM/RAM.
getLabelAddress

Syntax
emu.getLabelAddress(label)

Parameters
label - String
Label

Return value
Table - { address = int, memType = int }

Note: Returns nil when the specified label could not be found.

Description
Returns a table containing the address and memory type for the specified label.
getMemorySize

Syntax
emu.getMemorySize(memoryType)

Parameters
memoryType - Enum (memType)
Memory type

Return value
Int - Size of the specified memory type

Description
Returns the size (in bytes) of the specified memory type.
read

Syntax
emu.read(address, memoryType, signed)

Parameters
address - Int
Address to read from
memoryType - Enum (memType)
Memory type to read from
signed - Bool
When true, the return value is an 8-bit signed value.

Return value
Int - An 8-bit (signed or unsigned) value.

Description
Reads an 8-bit value from the specified address and memory type.

Note: When using "memType.[cpuName]" memory types, side-effects can occur from reading a value. Use the "memType.[cpuName]Debug" enum values to avoid side-effects.
read16

Syntax
emu.read16(address, memoryType, signed)

Parameters
address - Int
Address to read from
memoryType - Enum (memType)
Memory type to read from
signed - Bool
When true, the return value is a 16-bit signed value.

Return value
Int - A 16-bit (signed or unsigned) value.

Description
Reads a 16-bit value from the specified address and memory type.

Note: When using "memType.[cpuName]" memory types, side-effects can occur from reading a value. Use the "memType.[cpuName]Debug" enum values to avoid side-effects.
read32

Syntax
emu.read32(address, memoryType, signed)

Parameters
address - Int
Address to read from
memoryType - Enum (memType)
Memory type to read from
signed - Bool
When true, the return value is a 32-bit signed value.

Return value
Int - A 32-bit (signed or unsigned) value.

Description
Reads a 32-bit value from the specified address and memory type.

Note: When using "memType.[cpuName]" memory types, side-effects can occur from reading a value. Use the "memType.[cpuName]Debug" enum values to avoid side-effects.
write

Syntax
emu.write(address, value, memoryType)

Parameters
address - Int
Address to write to
value - Int
8-bit value to write
memoryType - Enum (memType)
Memory type to write to

Return value
<none>

Description
Writes an 8-bit value to the specified address and memory type.

Note: When using "memType.[cpuName]" memory types, side-effects can occur from writing a value. Use the "memType.[cpuName]Debug" enum values to avoid side-effects.
write16

Syntax
emu.write16(address, value, memoryType)

Parameters
address - Int
Address to write to
value - Int
16-bit value to write
memoryType - Enum (memType)
Memory type to write to

Return value
<none>

Description
Writes a 16-bit value to the specified address and memory type.

Note: When using "memType.[cpuName]" memory types, side-effects can occur from writing a value. Use the "memType.[cpuName]Debug" enum values to avoid side-effects.
write32

Syntax
emu.write32(address, value, memoryType)

Parameters
address - Int
Address to write to
value - Int
32-bit value to write
memoryType - Enum (memType)
Memory type to write to

Return value
<none>

Description
Writes a 32-bit value to the specified address and memory type.

Note: When using "memType.[cpuName]" memory types, side-effects can occur from writing a value. Use the "memType.[cpuName]Debug" enum values to avoid side-effects.
Miscellaneous
Access Counters
getAccessCounters

Syntax
emu.getAccessCounters(counterType, memoryType)

Parameters
counterType - Enum (counterType)
Counter type
memoryType - Enum (memType)
Memory type

Return value
Array - Array of ints

Description
Returns an array of access counters for the specified memory and operation types.
resetAccessCounters

Syntax
emu.resetAccessCounters()

Parameters
<none>

Return value
<none>

Description
Resets all access counters.
Cheats
addCheat

Syntax
emu.addCheat(cheatType, cheatCode)

Parameters
cheatType - Enum (cheatType)
Cheat type/format
cheatCode - String
Cheat code

Return value
<none>

Description
Adds the specified cheat code.

Note: Cheat codes added via this function are not permanent and not visible in the UI.
clearCheats

Syntax
emu.clearCheats()

Parameters
<none>

Return value
<none>

Description
Removes all active cheat codes.

Note: This has no impact on cheat codes saved in the UI, but it will disable them temporarily.
Save States
createSavestate

Syntax
emu.createSavestate()

Parameters
<none>

Return value
String - Binary string containing the savestate.

Description
Creates a savestate and returns it as a binary string.

Note: This can only be called from inside an "exec" memory callback.
loadSavestate

Syntax
emu.loadSavestate(state)

Parameters
state - String
Binary data containing the savestate

Return value
<none>

Description
Loads a savestate from a binary string.

Note: This can only be called from inside an "exec" memory callback.
Others
getRomInfo

Syntax
emu.getRomInfo()

Parameters
<none>

Return value
Table - { name = string, path = string, fileSha1Hash = string }

Description
Returns information about the ROM file that is currently running.
getScriptDataFolder

Syntax
emu.getScriptDataFolder()

Parameters
<none>

Return value
String - The folder's path

Description
This function returns the path to a unique folder (based on the script's filename) where the script should store its data (if any data needs to be saved). The data will be saved in subfolders inside the LuaScriptData folder in Mesen's home folder.

Note: This function will return an empty string if the "Allow access to I/O and OS functions" option is disabled.
takeScreenshot

Syntax
emu.takeScreenshot()

Parameters
<none>

Return value
String - A binary string containing a PNG image.

Description
Takes a screenshot and returns a PNG file as a string. The screenshot is not saved to the disk.
Enums
callbackType

Syntax
emu.callbackType.[value]

Description
Used by emu.addMemoryCallback() and emu.removeMemoryCallback()

Values
read - Callback is called when data is read
write - Callback is called when data is written
exec - Callback is called when the CPU starts executing an instruction
cheatType

Syntax
emu.cheatType.[value]

Description
Used by emu.addCheat()

Values
nesGameGenie - Game Genie (NES)
nesProActionRocky - Pro Action Rocky (NES)
nesCustom - Custom Address:Value code (NES)
gbGameGenie - Game Genie (GB)
gbGameShark - Game Shark (GB)
snesGameGenie - Game Genie (SNES)
snesProActionReplay - Pro Action Replay (SNES)
pceRaw - 24-bit address format (PC Engine)
pceAddress - 21-bit address format (PC Engine)
smsProActionReplay - Pro Action Replay (SMS)
smsGameGenie - Game Genie (SMS)
counterType

Syntax
emu.counterType.[value]

Description
Used by emu.getAccessCounters()

Values
readCount - Returns the number of times each byte was read
writeCount - Returns the number of times each byte was written
execCount - Returns the number of times each byte was executed
lastReadClock - Returns the time at which each byte was last read
lastWriteClock - Returns the time at which each byte was last written
lastExecClock - Returns the time at which each byte was last executed
cpuType

Syntax
emu.cpuType.[value]

Description
Used by several APIs to specify which CPU the API call applies to.

Values
snes - SNES - Main CPU - S-CPU 5A22 (65186)
spc - SNES - SPC
necDsp - SNES - DSP-n
sa1 - SNES - SA-1
cx4 - SNES - CX4
gameboy - Game Boy - Main CPU (can also be used in SGB mode)
nes - NES - Main CPU - 2A03 (6502)
pce - PC Engine - Main CPU - HuC6280
sms - SMS - Main CPU - Z80
gba - GBA - Main CPU - ARM7TDMI
drawSurface

Syntax
emu.drawSurface.[value]

Description
Used by emu.selectDrawSurface() and emu.getDrawSurfaceSize()

Values
consoleScreen - Console's framebuffer. Drawings appear in screenshots/videos.
scriptHud - Separate surface with a configurable resolution. Drawings not shown in screenshots/videos.
eventType

Syntax
emu.eventType.[value]

Description
Used by emu.addEventCallback() and emu.removeEventCallback()

Values
nmi - Triggered when an NMI occurs (not available on some consoles)
irq - Triggered when an IRQ occurs
startFrame - Triggered when a frame starts (typically once vertical blank ends)
endFrame - Triggered when a frame ends (typically once vertical blank starts)
reset - Triggered when the console is reset (not available on some consoles)
scriptEnded - Triggered when the Lua script is stopped
inputPolled - Triggered after the emulator updates the state of all input devices (once per frame)
stateLoaded - Triggered when a savestate is manually loaded
stateSaved - Triggered when a savestate is manually saved
codeBreak - Triggered when code execution breaks (e.g breakpoint, step, etc.)
memType

Syntax
emu.memType.[value]

Description
Used by several APIs to specify which memory type to access/use.

Values
snesMemory - SNES - S-CPU memory
spcMemory - SNES - SPC memory
sa1Memory - SNES - SA-1 memory
necDspMemory - SNES - DSP-n memory
gsuMemory - SNES - GSU memory
cx4Memory - SNES - CX4 memory
gameboyMemory - Game Boy - CPU memory
nesMemory - NES - CPU memory
nesPpuMemory - NES - PPU memory
pceMemory - PC Engine - CPU memory
smsMemory - SMS - CPU memory
gbaMemory - GBA - CPU memory
snesDebug - SNES - S-CPU memory (no read/write side-effects)
spcDebug - SNES - SPC memory (no read/write side-effects)
sa1Debug - SNES - SA-1 memory (no read/write side-effects)
necDspDebug - SNES - DSP-n memory (no read/write side-effects)
gsuDebug - SNES - GSU memory (no read/write side-effects)
cx4Debug - SNES - CX4 memory (no read/write side-effects)
gameboyDebug - Game Boy - CPU memory (no read/write side-effects)
nesDebug - NES - CPU memory (no read/write side-effects)
nesPpuDebug - NES - PPU memory (no read/write side-effects)
pceDebug - PC Engine - CPU memory (no read/write side-effects)
smsDebug - SMS - CPU memory (no read/write side-effects)
gbaDebug - GBA - CPU memory (no read/write side-effects)
snesPrgRom - SNES - PRG ROM
snesWorkRam - SNES - Work RAM
snesSaveRam - SNES - Save RAM
snesVideoRam - SNES - Video RAM
snesSpriteRam - SNES - Sprite RAM (OAM)
snesCgRam - SNES - Palette RAM (CGRAM)
spcRam - SNES - SPC - RAM
spcRom - SNES - SPC - IPL ROM
dspProgramRom - SNES - DSP-n - Program ROM
dspDataRom - SNES - DSP-n - Data ROM
dspDataRam - SNES - DSP-n - Data RAM
sa1InternalRam - SNES - SA-1 - IRAM
gsuWorkRam - SNES - GSU - Work RAM
cx4DataRam - SNES - CX4 - Data RAM
bsxPsRam - SNES - BS-X - PSRAM
bsxMemoryPack - SNES - BS-X - Memory Pack
gbPrgRom - Game Boy - PRG ROM
gbWorkRam - Game Boy - Work RAM
gbCartRam - Game Boy - Cart/Save RAM
gbHighRam - Game Boy - High RAM
gbBootRom - Game Boy - Boot ROM
gbVideoRam - Game Boy - Video RAM
gbSpriteRam - Game Boy - Sprite RAM
nesPrgRom - NES - PRG ROM
nesInternalRam - NES - System RAM
nesWorkRam - NES - Work RAM
nesSaveRam - NES - Save RAM
nesNametableRam - NES - Nametable RAM (CIRAM)
nesSpriteRam - NES - Sprite RAM (OAM)
nesSecondarySpriteRam - NES - Secondary Sprite RAM
nesPaletteRam - NES - Palette RAM
nesChrRam - NES - CHR RAM
nesChrRom - NES - CHR ROM
pcePrgRom - PC Engine - HuCard ROM
pceWorkRam - PC Engine - Work RAM
pceSaveRam - PC Engine - Save RAM
pceCdromRam - PC Engine - CD-ROM Unit RAM
pceCardRam - PC Engine - Card RAM
pceAdpcmRam - PC Engine - ADPCM RAM
pceArcadeCardRam - PC Engine - Arcade Card RAM
pceVideoRam - PC Engine - Video RAM (VDC)
pceVideoRamVdc2 - PC Engine - Video RAM (VDC2 - SuperGrafx only)
pceSpriteRam - PC Engine - Sprite RAM (VDC)
pceSpriteRamVdc2 - PC Engine - Sprite RAM (VDC2 - SuperGrafx only)
pcePaletteRam - PC Engine - Palette RAM (VCE)
smsPrgRom - SMS - ROM
smsWorkRam - SMS - System RAM
smsCartRam - SMS - Cart RAM
smsBootRom - SMS - BIOS ROM
smsVideoRam - SMS - Video RAM
smsPaletteRam - SMS - Palette RAM
smsPort - SMS - I/O Port
gbaPrgRom - GBA - ROM
gbaIntWorkRam - GBA - Internal Work RAM
gbaExtWorkRam - GBA - External Work RAM
gbaSaveRam - GBA - Save RAM/Flash/EEPROM
gbaBootRom - GBA - BIOS ROM
gbaVideoRam - GBA - Video RAM
gbaSpriteRam - GBA - Sprite RAM
gbaPaletteRam - GBA - Palette RAM
stepType

Syntax
emu.stepType.[value]

Description
Used by emu.step()

Values
step - Steps the specified number of instructions
stepOut - Steps out of the current subroutine (not available for all CPUs)
stepOver - Steps over the current subroutine call (not available for all CPUs)
cpuCycleStep - Steps the specified number of CPU cycles (not available for all CPUs)
ppuStep - Steps the specified number of scanline cycles
ppuScanline - Steps the specified number of scanlines
ppuFrame - Steps the specified number of video frames
specificScanline - Breaks on the specified scanline number
runToNmi - Breaks on the next NMI event
runToIrq - Breaks on the next IRQ event

--NES游戏似乎不支持read16,read32,write16,write32.

read / readWord

Syntax

emu.read(address, type, signed = false)
emu.readWord(address, type, signed = false)

Parameters
address - Integer The address/offset to read from.
type - Enum The type of memory to read from. See memType.
signed - (optional) Boolean If true, the value returned will be interpreted as a signed value.

Return value
An 8-bit (read) or 16-bit (readWord) value.

Description
Reads a value from the specified memory type.

When calling read / readWord with the memType.cpu or memType.ppu memory types, emulation side-effects may occur.
To avoid triggering side-effects, use the memType.cpuDebug or memType.ppuDebug types, which will not cause side-effects.
write / writeWord

Syntax

emu.write(address, value, type)
emu.writeWord(address, value, type)

Parameters
address - Integer The address/offset to write to.
value - Integer The value to write.
type - Enum The type of memory to write to. See memType.

Return value
None

Description
Writes an 8-bit or 16-bit value to the specified memory type.

Normally read-only types such as PRG-ROM or CHR-ROM can be written to when using memType.prgRom or memType.chrRom.
Changes will remain in effect until a power cycle occurs.
To revert changes done to ROM, see revertPrgChrChanges.

When calling write / writeWord with the memType.cpu or memType.ppu memory types, emulation side-effects may occur.
To avoid triggering side-effects, use the memType.cpuDebug or memType.ppuDebug types, which will not cause side-effects.
revertPrgChrChanges

Syntax

emu.revertPrgChrChanges()

Return value
None

Description
Reverts all modifications done to PRG-ROM and CHR-ROM via write/writeWord calls.
getPrgRomOffset

Syntax

emu.getPrgRomOffset(address)

Parameters
address - Integer A CPU address (Valid range: $0000-$FFFF)

Return value
Integer The corresponding byte offset in PRG ROM

Description
Returns an integer representing the byte offset of the specified CPU address in PRG ROM based on the mapper’s current configuration. Returns -1 when the specified address is not mapped to PRG ROM.(Mesen2.x已弃用)
getChrRomOffset

Syntax

emu.getChrRomOffset(address)

Parameters
address - Integer A PPU address (Valid range: $0000-$3FFF)

Return value
Integer The corresponding byte offset in CHR ROM

Description
Returns an integer representing the byte offset of the specified PPU address in CHR ROM based on the mapper’s current configuration. Returns -1 when the specified address is not mapped to CHR ROM.(Mesen2.x已弃用)
getLabelAddress

Syntax

emu.getLabelAddress(label)

Parameters
label - String The label to look up

Return value
Integer The corresponding CPU address

Description
Returns the address of the specified label. This address can be used with the memory read/write functions (read(), readWord(), write(), writeWord()) using the emu.memType.cpu or emu.memType.cpuDebug memory types.