I don't have a bios or roms so I cannot confirm on my MacBook but the default source lists as follows.
Controls:
Arrow keys + L = Default joystick 1 emulation
W,D,S,A + Space = Default joystick 2 emulation
ESC/F12 = Leave the emulator
F1 = Pause/Information
F2 = Save State-File
F3 = Load State-File
F4 = Enter debugger
F5 = Reset emulator (same as pressing the reset on the O2 keyboard)
F6 = Inject Highscore
F8 = Make a screen shot
Caps Lock = Enables/Disables the O2 keyboard input of the keys used by
joystick emulation