Provided by:
sdlmame_0.123-0ubuntu1_i386 
NAME
joymap.dat - SDLMAME joystick mapping file
DESCRIPTION
With hot-pluggable devices like USB joystick is almost unpredictable
which one will be enumerated first by SDLMAME. This can easily lead to
unwanted joystick switchings.
With the joymap file, one can put each joystick into a logical slot,
i.e. map it to a logical number SDLMAME will use.
FILE FORMAT
Each line of the file could be
a comment, starting with # (hash sign), which will be ignored.
a pair of values, representing the SDLMAME logical_number and
the joystick name. The name of each connected joystick can be
determined with the jstest joystick test program.
EXAMPLE
# Joystick mapping file
# =====================
#
# Contains mapping between name and logical (i.e. mame) joystick index
#
# Index Name
# ----- ----
1 MOSIC USB 2A4K GamePad
0 Logitech Logitech Attack 3
This file will map joystick "MOSIC USB 2A4K GamePad" to SDLMAME id 1
and "Logitech Logitech Attack 3" to SDLMAME id 0.
HINTS
If a joystick is not found and you have mapped SDLMAME codes in the ui
to it, SDLMAME will just display "n/a". Connect the joystick, restart
SDLMAME and the mappings will be there again.
Joysticks which are not mapped will be put into free slots.
EXAMPLE: You have mapped a joystick to slot 1. Connect a second
joystick and it will be mapped to slot 0. A third would be mapped to
slot 2.
If you don’t know the name of your joystick, first look at device names
with ls -l /dev/input/js* and do jstest /dev/input/js... for each of
them. The joystick name is the text enclosed in round brackets.
EXAMPLE: if you find you have two joysticks connected, /dev/input/js0
and /dev/input/js1, you have to run jstest /dev/input/js0 and then
jstest /dev/input/js1.
SEE ALSO
jstest(1), sdlmame(6).