debugger-command-help
displays built-in help in the console
debugger-command-do
evaluates the given expression
debugger-command-symlist
lists registered symbols
debugger-command-softreset
executes a soft reset
debugger-command-hardreset
executes a hard reset
debugger-command-print
prints one or more <item>s to the console
debugger-command-printf
prints one or more <item>s to the console using <format>
debugger-command-logerror
outputs one or more <item>s to the error.log
debugger-command-tracelog
outputs one or more <item>s to the trace file using <format>
debugger-command-tracesym
outputs one or more <item>s to the trace file
debugger-command-history
displays recently visited PC addresses and opcodes
debugger-command-trackpc
visually track visited opcodes
debugger-command-trackmem
record which PC writes to each memory address
debugger-command-pcatmem
query which PC wrote to a given memory address
debugger-command-rewind
go back in time by loading the most recent rewind state
debugger-command-statesave
save a state file for the emulated system
debugger-command-stateload
load a state file for the emulated system
debugger-command-snap
save a screen snapshot
debugger-command-source
read commands from file and executes them one by one
debugger-command-time
prints the current machine time to the console
debugger-command-quit
exit the debugger and end the emulation session
help [<topic>]
Displays built-in debugger help in the debugger console. If no <topic> is specified, top-level topics are listed. Most debugger commands have correspondingly named help topics.
Examples:
help
Lists top-level help topics.
help expressions
Displays built-in help for debugger expression syntax.
help wpiset
Displays built-in help for the
wpiset <debugger-command-wpset>
command.
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do <expression>
The do command simply evaluates the supplied expression. This is often used to set or modify device state variable (e.g. CPU registers), or to write to memory. See debugger-express
for details about expression syntax.
Examples:
do pc = 0
Sets the register pc to 0.
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symlist [<cpu>]
Lists registered symbols and their values. If <cpu> is not specified, symbols in the global symbol table are displayed; otherwise, symbols specific to the device <cpu> are displayed. Symbols are listed alphabetically. Read-only symbols are noted. See debugger-devicespec
for details on how to specify a CPU.
Examples:
symlist
Displays the global symbol table.
symlist 2
Displays the symbols for the third CPU in the system (zero-based index).
symlist audiocpu
Displays symbols for the CPU with the absolute tag
:audiocpu
.
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softreset
Executes a soft reset. This calls the reset member functions of all the devices in the system (by default, pressing F3 during emulation has the same effect).
Examples:
softreset
Executes a soft reset.
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hardreset
Executes a hard reset. This tears down the emulation session and starts another session with the same system and options (by default, pressing Shift+F3 during emulation has the same effect). Note that this will lose history in the debugger console and error log.
Examples:
hardreset
Executes a hard reset.
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print <item>[,…]
The print command prints the results of one or more expressions to the debugger console as hexadecimal numbers.
Examples:
print pc
Prints the value of the pc register the console as a hex number.
print a,b,a+b
Prints a, b, and the value of a+b to the console as hex numbers.
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printf <format>[,<argument>[,…]]
Prints a C-style formatted message to the debugger console. Only a very limited subset of format specifiers and escape sequences are available:
- %c
Prints the corresponding argument as an 8-bit character.
- %[0][<n>]d
Prints the corresponding argument as a decimal number with optional minimum field width and zero fill.
- %[0][<n>]o
Prints the corresponding argument as an octal number with optional minimum field width and zero fill using lowercase letters.
- %[0][<n>]x
Prints the corresponding argument as a hexadecimal number with optional minimum field width and zero fill using uppercase letters.
- %%
Prints a literal percent symbol.
- \n
Prints a line break.
- \\
Prints a literal backslash.
All other format specifiers are ignored.
Examples:
printf "PC=%04X",pc
Prints
PC=<pcval>
where <pcval> is the hexadecimal value of the pc register with a minimum of four digits and zero fill.printf "A=%d, B=%d\\nC=%d",a,b,a+b
Prints
A=<aval>, B=<bval>
on one line, andC=<a+bval>
on a second line.
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logerror <format>[,<argument>[,…]]
Prints a C-style formatted message to the error log. See debugger-command-printf
for details about the limited set of supported format specifiers and escape sequences.
Examples:
logerror "PC=%04X",pc
Logs
PC=<pcval>
where <pcval> is the hexadecimal value of the pc register with a minimum of four digits and zero fill.logerror "A=%d, B=%d\\nC=%d",a,b,a+b
Logs
A=<aval>, B=<bval>
on one line, andC=<a+bval>
on a second line.
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tracelog <format>[,<argument>[,…]]
Prints a C-style formatted message to the currently open trace file (see debugger-command-trace
for more information). If no trace file is open, this command has no effect. See debugger-command-printf
for details about the limited set of supported format specifiers and escape sequences.
Examples:
tracelog "PC=%04X",pc
Outputs
PC=<pcval>
where <pcval> is the hexadecimal value of the pc register with a minimum of four digits and zero fill if a trace log file is open.tracelog "A=%d, B=%d\\nC=%d",a,b,a+b
Outputs
A=<aval>, B=<bval>
on one line, andC=<a+bval>
on a second line if a trace log file is open.
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tracesym <item>[,…]
Prints the specified symbols to the currently open trace file (see debugger-command-trace
for more information). If no trace file is open, this command has no effect.
Examples:
tracesym pc
Outputs
PC=<pcval>
where <pcval> is the value of the pc register in its default format if a trace log file is open.
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history [<CPU>[,<length>]]
Displays recently visited PC addresses, and disassembly of the instructions at those addresses. If present, the first argument selects the CPU (see debugger-devicespec
for details); if no CPU is specified, the visible CPU is assumed. The second argument, if present, limits the maximum number of addresses shown. Addresses are shown in order from least to most recently visited.
Examples:
history ,5
Displays up to five most recently visited PC addresses and instructions for the visible CPU.
history 3
Displays recently visited PC addresses and instructions for the fourth CPU in the system (zero-based index).
history audiocpu,1
Displays the most recently visited PC address and instruction for the CPU with the absolute tag
:audiocpu
.
trackpc [<enable>[,<CPU>[,<clear>]]]
Turns visited PC address tracking for disassembly views on or off. Instructions at addresses visited while tracking is on are highlighted in debugger disassembly views. The first argument is a Boolean specifying whether tracking should be turned on or off (defaults to on). The second argument specifies the CPU to enable or disable tracking for (see debugger-devicespec
for details); if no CPU is specified, the visible CPU is assumed. The third argument is a Boolean specifying whether existing data should be cleared (defaults to false).
Examples:
trackpc 1
Begin or tracking the current CPU’s PC.
trackpc 1,0,1
Begin or continue tracking PC on the first CPU in the system (zero-based index), but clear the history tracked so far.
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trackmem [<enable>,[<CPU>,[<clear>]]]
Enables or disables logging the PC address each time a memory address is written to. The first argument is a Boolean specifying whether tracking should be enabled or disabled (defaults to enabled). The second argument specifies the CPU to enable or disable tracking for (see debugger-devicespec
for details); if no CPU is specified, the visible CPU is assumed. The third argument is a Boolean specifying whether existing data should be cleared (defaults to false).
Use debugger-command-pcatmem
to retrieve this data. Right-clicking a debugger memory view will also display the logged PC value for the given address in some configurations.
Examples:
trackmem
Begin or continue tracking memory writes for the visible CPU.
trackmem 1,0,1
Begin or continue tracking memory writes for the first CPU in the system (zero-based index), but clear existing tracking data.
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pcatmem[{d|i|o}] <address>[:<space>]
Returns the PC value at the time the specified address was most recently written to. The argument is the requested address, optionally followed by a colon and a CPU and/or address space (see debugger-devicespec
for details). The optional d, i or o suffix controls the default address space for the command.
Tracking must be enabled for the data this command uses to be recorded (see debugger-command-trackmem
). Right-clicking a debugger memory view will also display the logged PC value for the given address in some configurations.
Examples:
pcatmem 400000
Print the PC value when location 400000 in the visible CPU’s program space was most recently written.
pcatmem 3bc:io
Print the PC value when location 3bc in the visible CPU’s
io
space was most recently written.pcatmem 1400:audiocpu
Print the PC value when location 1400 in the CPU
:audiocpu
’s program space was most recently written.
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rewind
Loads the most recent RAM-based saved state. When enabled, rewind states are saved when debugger-command-step
, debugger-command-over
and debugger-command-out
commands are used, storing the machine state as of the moment before stepping. May be abbreviated to rw
.
Consecutively loading rewind states can work like reverse execution. Depending on which steps forward were taken previously, the behavior can be similar to GDB's reverse-stepi and reverse-next commands. All output for this command is currently echoed into the running machine window.
Previous memory and PC tracking statistics are cleared. Actual reverse execution does not occur.
Examples:
rewind
Load the previous RAM-based save state.
rw
Abbreviated form of the command.
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statesave <filename>
Creates a save state at the current moment in emulated time. The state file is written to the configured save state directory (see the state_directory <mame-commandline-statedirectory>
option), and the .sta extension is automatically appended to the specified file name. May be abbreviates to ss
.
All output from this command is currently echoed into the running machine window.
Examples:
statesave foo
Saves the emulated machine state to the file foo.sta in the configured save state directory.
ss bar
Abbreviated form of the command – saves the emulated machine state to bar.sta.
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stateload <filename>
Restores a saved state file from disk. The specified state file is read from the configured save state directory (see the state_directory <mame-commandline-statedirectory>
option), and the .sta extension is automatically appended to the specified file name. May be abbreviated to sl
.
All output for this command is currently echoed into the running machine window. Previous memory and PC tracking statistics are cleared.
Examples:
stateload foo
Loads state from file foo.sta to the configured save state directory.
sl bar
Abbreviated form of the command – loads the file bar.sta.
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snap [<filename>[,<scrnum>]]
Takes a snapshot of the emulated video display and saves it to the configured snapshot directory (see the snapshot_directory <mame-commandline-snapshotdirectory>
option). If a file name is specified, a single screenshot for the specified screen is saved using the specified filename (or the first emulated screen in the system if a screen is not specified). If a file name is not specified, the configured snapshot view and file name pattern are used (see the snapview <mame-commandline-snapview>
and snapname <mame-commandline-snapname>
options).
If a file name is specified, the .png extension is automatically appended. The screen number is specified as a zero-based index, as seen in the names of automatically-generated single-screen views in MAME’s video options menus.
Examples:
snap
Takes a snapshot using the configured snapshot view and file name options.
snap shinobi
Takes a snapshot of the first emulated video screen and saves it as shinobi.png in the configured snapshot directory.
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source <filename>
Reads the specified file in text mode and executes each line as a debugger command. This is similar to running a shell script or batch file.
Examples:
source break_and_trace.cmd
Reads and executes debugger commands from break_and_trace.cmd.
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Prints the total elapsed emulated time to the debugger console.
Examples:
time
Prints the elapsed emulated time.
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quit
Closes the debugger and ends the emulation session immediately. Either exits MAME or returns to the system selection menu, depending on whether the system was specified on the command line when starting MAME.
Examples:
quit
Exits the emulation session immediately.
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